Gothic II sucked me in at first with some pleasant-looking landscapes, nice musical backdrop, and interesting lore. After a few hours of game time I started to notice the enormous amount of flaws with this game. Man, where to start?
The inventory is a jumbled mass of knicknacks, trinkets, garbage, and unusable weapons that you accumulate with seemingly no organization at all. The combat system doesn't seem to allow you to transition very easily from melee to magic fighting, so I'll be standing there getting bitten to death by wolves while my character spastically struggles to unsheath his sword. Many of the quests I picked up were bugged and impossible to complete for various reasons. Sometimes certain quests were entered into my questbook, which is also hopelessly disorganized, and I spent far too many minutes sifting through the entries trying to find a clue as to what I should be doing.
And the difficulty level is off the charts. I usually play games on the most difficult setting when possible, because I enjoy a challenge, but in Gothic II it felt as if quests just kept piling up because I was nowhere NEAR powerful enough to complete most of them when I picked them up. "Recover the Eye of Innos? Oh, okay, let me just rush into the middle of these five demonic sorcerers, any ONE of which could kill me by sneezing in my direction!"
IT also struck me as rather funny that even after I became a big, bad Fire Mage, any old nameless Citizen in town could sometimes beat me up with a twig. And a few times, this would happen with no provocation on my part. And even though someone else will start a fight, everyone else accuses me of being a thug and descend on me with sabers and flying fisticuffs.
This game is riddled with flaws. The voice acting is laughably bad. The character models look like a 4th grader drew them. And even the pixellated little people in the game are so depressed about living in such a shoddy place that they constantly quaff Gin straight from the bottle. It has sunk me into a black despondency, and I am now going to go live under the overpass, away from the warm glow of computer screens, away from the terrible temptation of Gothic II, where maybe I can finally get some placid sleep without the looming threat of death by Bloodfly.

Gothic 2 happens to be my favourite RPG, so I decided to write a few words here. I completely disagree with most of your points.
It is a valid complaint, the inventory definitely could have been much better. But is far from unusable. Weapons are sorted first by type (melee or ranged), then by damage. And you should sell all the junk instead of accumulating it ;).
It's supposed to work this way. You should focus on one way of fighting and not change your weapons in the middle of a fight unless necessary. And you can unsheathe your sword while running.
I would really like to see some examples. The only serious bug I am aware of is linked to dialogue with Lares. I know there are glitches, but they are definitely not that frequent. At least I didn't encounter them (and I've played the game four times).
I didn't have the problem with it. The new quests are added to the top of the list, new entries are added to the right “thread” as the quest progresses. And I found the descriptions to be clear enough. I am happy that authors didn't include an arrow pointing you to the your destination.
Are you playing with “Night of the Raven” installed? If so – this is your problem. The expansion was meant for veterans of original Gothic 2, and increased difficulty considerably.
The citizens do not attack you unless provoked. Never (unless it is some weird bug which I doubt). Provoking includes walking with your weapon unsheathed (or battles spells prepared), walking into peoples houses, pickpocketing (if detected) and stealing.
I can't comment on this since I didn't play English version.
It's an old game. It wasn't beautiful when it was released but it wasn't repellent either.
Maybe some of your problems are the result of your choice of being a mage. I have always chosen a warrior path so I can't comment on this.

"It is a valid complaint, the inventory definitely could have been much better. But is far from unusable. Weapons are sorted first by type (melee or ranged), then by damage. And you should sell all the junk instead of accumulating it ;)."
- Yes, the inventory system is usable, and there might be some rationale for it, but it seems completely inefficient and non-intuitive. Objects are sorted according to something, but they still just pile up on one big grid full of difficult-to-distinguish plants, rings, brooms, swords, claws, etc. There is no character screen that allows you to see what you have equipped on what body part. That makes it more difficult than it should be to swap out gear.
"It's supposed to work this way. You should focus on one way of fighting and not change your weapons in the middle of a fight unless necessary. And you can unsheathe your sword while running."
-I really had my heart set on playing a warrior/mage, as I find simply standing there casting fireball after fireball *Poof poof poof dead* to be pretty dull. Especially since the melee combat system is actually very well done, and I wanted to integrate that into a caster combat mode. So, while it may be intentional that you cannot play like a hybrid warrior/mage, it is disappointing.
"Many of the quests I picked up were bugged and impossible to complete for various reasons."
"I would really like to see some examples. The only serious bug I am aware of is linked to dialogue with Lares. I know there are glitches, but they are definitely not that frequent. At least I didn't encounter them (and I've played the game four times)."
- I reached a point where Lares had just said he would escort me out of the city because Baltram would get a replacement, and then the dialogue option disappeared. I do not know why.
Also, my first play through a while back I got stuck progressing the story along because the water mages at the pyramid asked me to get something from Vatras, but he did not offer me an option in the dialogue to obtain that item. And after looking up information on this quest online for a while, I had no solution and had to abandon the game.
One of the mages at the monastery offered me a quest at one point, which I put off completing for a bit, and then offered me no more dialogue options at all, and I could not find the quest in my questbook.
"I didn't have the problem with it. The new quests are added to the top of the list, new entries are added to the right “thread” as the quest progresses. And I found the descriptions to be clear enough. I am happy that authors didn't include an arrow pointing you to the your destination."
- When you are wandering around picking up multiple quests from multiple people, and they are just piling up like crazy in your questbook, it becomes difficult to find which quest line THIS object is for, or which questline THAT guy is relevant to, etc.
Like the inventory system, yes, it works, but not nearly as well as quest logs in many other games I've played. Yes, quests are added to the top of the list as you pick them up, but when you pick up subsequent bits of information or objects relating to that quest, it just says "Quest Diary Updated" or whatever, without telling you which quest was updated/completed or whatever.
"Are you playing with “Night of the Raven” installed? If so – this is your problem. The expansion was meant for veterans of original Gothic 2, and increased difficulty considerably."
- Yes, I am playing with NoTR installed. I understand that it is a great deal more content, and I didn't want to miss out on that.
"IT also struck me as rather funny that even after I became a big, bad Fire Mage, any old nameless Citizen in town could sometimes beat me up with a twig. And a few times, this would happen with no provocation on my part. And even though someone else will start a fight, everyone else accuses me of being a thug and descend on me with sabers and flying fisticuffs."
"The citizens do not attack you unless provoked. Never (unless it is some weird bug which I doubt). Provoking includes walking with your weapon unsheathed (or battles spells prepared), walking into peoples houses, pickpocketing (if detected) and stealing."
- Not true. I freed Joe from the tower, and the next time he saw me in the tavern, he began swinging fists at me, without my having attacked him or interacted with him at all. And then everyone else in the harbor district started beating me. I reloaded from an earlier save point, but he would attack me every time just as soon as I got anywhere near the tavern. And the other citizens held ME accountable for it.
Also, when one of the mercenaries at Onar's farm challenged me to a "duel", I began fighting him (with my melee weapon) and everyone got pissed and starting attacking me as if I had started the fight.
"Maybe some of your problems are the result of your choice of being a mage. I have always chosen a warrior path so I can't comment on this."
-That is possible.

The random beatings is definitely a bug. Friendly NPCs only attack you if you attack them first, kill someone with witnesses nearby, enter a restricted area, or continue having a weapon/magic drawn after being warned several times to put it away.
Night of the Raven is renowned for being unreasonably difficult. It should only be attempted by veterans of the series, and even then you have to know your way around the game and plan out your levelling and equipment upgrades and such in advance. Even if you do everything right there are several points where you will find yourself woefully underpowered.

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- Yes, the inventory system is usable, and there might be some rationale for it, but it seems completely inefficient and non-intuitive. Objects are sorted according to something, but they still just pile up on one big grid full of difficult-to-distinguish plants, rings, brooms, swords, claws, etc. There is no character screen that allows you to see what you have equipped on what body part. That makes it more difficult than it should be to swap out gear.
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I agree that it could use considerable improvements. I don't think that character screen is necessary however. All you can equip is melee weapon (1), ranged weapon (2), spells, armour, belt (only in expansion), two rings and an amulet. These are kept close to each other in the inventory if I remember correctly. But separate groups for objects would be nice (they were present in Gothic 1 but got removed in the sequel for whatever reason).
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-I really had my heart set on playing a warrior/mage, as I find simply standing there casting fireball after fireball *Poof poof poof dead* to be pretty dull. Especially since the melee combat system is actually very well done, and I wanted to integrate that into a caster combat mode. So, while it may be intentional that you cannot play like a hybrid warrior/mage, it is disappointing.
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That is partially connected to the expansions difficulty. You have to plan ahead, and there is very little place for experiments. I will explain it further at the end of my post.
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- I reached a point where Lares had just said he would escort me out of the city because Baltram would get a replacement, and then the dialogue option disappeared. I do not know why.
Also, my first play through a while back I got stuck progressing the story along because the water mages at the pyramid asked me to get something from Vatras, but he did not offer me an option in the dialogue to obtain that item. And after looking up information on this quest online for a while, I had no solution and had to abandon the game.
One of the mages at the monastery offered me a quest at one point, which I put off completing for a bit, and then offered me no more dialogue options at all, and I could not find the quest in my questbook.
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The first bug was what I mentioned. It has been discussed here:
http://www.gog.com/en/forum/gothic_series/warning_major_night_of_the_raven_bug_with_lares
There are some claims that dialogue option becomes available again in act 3, but this is definitely a thing that should have been tested better. As for the last one - a mage quest, so I can't comment on it.
I am aware that there are bugs in the game, but I am surprised that you had such bad luck, that you experienced possibly every single glitch in the game. On my play-throughs I didn't find any of this. I guess I just really like the game and it responds accordingly ;). I'm sorry to hear that you had such a bad experience.
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- When you are wandering around picking up multiple quests from multiple people, and they are just piling up like crazy in your questbook, it becomes difficult to find which quest line THIS object is for, or which questline THAT guy is relevant to, etc.
Like the inventory system, yes, it works, but not nearly as well as quest logs in many other games I've played. Yes, quests are added to the top of the list as you pick them up, but when you pick up subsequent bits of information or objects relating to that quest, it just says "Quest Diary Updated" or whatever, without telling you which quest was updated/completed or whatever.
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Yes, it could have been better. But it is working as intended. When I ask a guy about missing people, I get a new entry in the "Missing people" quest. If I talk to a guy, and he says that he has been attacked by a bunch of bandits with tons of weaponry, I get a new entry in "The Bandits' Weapon Dealer" quest.
And again I think it may be somehow linked to Night of the Raven. When I was playing, I could easily link most dialogues with their corresponding quests in my head. But that may have been a result of my former knowledge of the world and knowing "who is who, where they are and what they want". I could just "filter" older quests from new ones. I realise that dealing with all that content during first game may be troublesome.
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- Yes, I am playing with NoTR installed. I understand that it is a great deal more content, and I didn't want to miss out on that.
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I will repeat - this is your main problem. It wasn't really an add-on - it was an add-in. It required original Gothic 2 to be installed and designers assumed that the player will be familiar with the setting and game mechanics.
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- Not true. I freed Joe from the tower, and the next time he saw me in the tavern, he began swinging fists at me, without my having attacked him or interacted with him at all. And then everyone else in the harbor district started beating me. I reloaded from an earlier save point, but he would attack me every time just as soon as I got anywhere near the tavern. And the other citizens held ME accountable for it.
Also, when one of the mercenaries at Onar's farm challenged me to a "duel", I began fighting him (with my melee weapon) and everyone got pissed and starting attacking me as if I had started the fight.
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Again. You have a terrible bad luck. Joe never had a problem with me (even if I wiped out the thief guild :P). I actually may have experienced the second bug once, but reloading helped in my case.
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I see that most of your problems are a result of Night of the Raven.
Saturas, Lares and Joe are all characters that appear in expansion only. I would really recommend trying the game without it. The difficulty was added because authors received complaints that Gothic 2 was "too easy", and they decided to repair that mistake - they sure did. It was meant for people who completed the game several times and knew every little detail and trick about the game. Personally I found it to be "pleasantly challenging" :). But someone who isn't familiar with the game is likely to be eaten alive. It just isn't meant to be played that way - you have to plan ahead, and without completing the game before it is hard to do.
Another reason why I think you should try playing original without expansion, is because character development is much easier, and your hybrid class may actually prove useful (again - I didn't play with magic so I can't tell for sure).
If you don't want to miss content - well, that is unavoidable anyway, because you have to choose a faction and many side quests are bound to that choice. Once you are familiar with the world you may want to try and replay the game with different faction and different choices, and with NotR this time.
We just have a different view on this game. Things that you find game-breaking for me are just minor annoyances. I have experienced very few glitches - you have been surrounded by them.
I realise that you probably don't want to touch this game any more, and honestly I understand. But I thought I should post my "counter-warning", since I know that there are people who share my view, and this discussion may prove useful to anyone trying to gather information on this game.
Edit: I just realised that I made a mistake that I need to clarify. Lares does appear in original Gothic 2, but he doesn't have these "bugged" dialogue options.

Thanks for the articulate responses, Paradoks. I don't mean to say I haven't enjoyed playing it whatsoever, it just seems, as you said, that I experienced more of the bugs and glitches than most people. But there certainly are some wonderful things about the game. And some of the frustrations I was having are ameliorated somewhat by playing the game enough that I can look past them, or get used to them. I had not known that I was getting myself into such a world of hurt by playing with the Night of the Raven Add-in. But I am not giving up on the game yet. I started getting absorbed in it again, and I want to play it through to the end, because the storyline is actually rather compelling. I do wish I had planned out where I would allocate my experience points better, though. After this playthrough I may very well uninstall NoTR and try a game as a merc.
Anyways, for 6 dollars, I'd still recommend this game to most fans of immersive RPGs.

I had a similar experience to the OP on my first run-through. This game was just balls-to-the-wall hard which made me hunger for more pain. It became progressively easier once I had enough money from stealing to buy every health potion available, make my own and buy a heck of a lot of scrolls. Quicksaves and hotkeys for health/mana potions greatly ameliorated the difficulty.
If the difficulty is too difficult by lvl 10 or your character got screwed up you might want to look up Marvin-Mode. Save before you do so and exercise discretion with giving your character bountiful assets. Great funkiness can ensue.
Something that can also be beneficial but hard to achieve is a character of around lvl 4-6 who remains uncommited to any faction but has money and a good amount of free stat points. It becomes a blank coin which your whimsical die can shape thus cutting down on character creation time.

The first time i played Gothic 2 was with the NOTR expansion and it was tough but if you act patient and save often, you should be okay. If something is to hard then improve in a certain area or change strategies. If you practice enough with the sword fighting system you should be able to handle encounters pretty well despite what level you may be on. Don't spread your self out too early and focus on certain area's at first. If there is a place is too difficult, go somewhere else or go around your obstacle. Also where the appropriate outfit in certain places, they will attack you if you dress up like their enemy.
The first time i played Gothic 2 was with the NOTR expansion and it was tough but if you act patient and save often, you should be okay. If something is to hard then improve in a certain area or change strategies. If you practice enough with the sword fighting system you should be able to handle encounters pretty well despite what level you may be on. Don't spread your self out too early and focus on certain area's at first. If there is a place is too difficult, go somewhere else or go around your obstacle. Also where the appropriate outfit in certain places, they will attack you if you dress up like their enemy.

Gothic I and II actually have a fairly decent approach to magic. Unlike other systems where you become so ridiculously powerful (stopping time and raining down fireballs from the heavens), the magic system is actually done in such away as to make the game world realistic. You CAN be powerful, but don't expect to run into a group of Dragon Hunters and just rain down death
You won't ever be an Eliminster type solo mage with rapid fire spells shooting out of your fingers. In reality, you'll play more like a battle mage. You'll need some weapon ability to complement your spells.

Please tell me that you didn't run into town with bandit or pirate armor. Please tell me that.

That post really made me laugh. Have you actually played the whole game through with a mage?
I can't speak for Gothic 1 (I haven't gotten around to playing it yet) but imho Gothic 2 has one of the worst balanced magic system in any RPG. Basically, while fighter types can raise strenght and find good weapons early on, a mage's spells are granted by the guild, based on the chapter you're in.
This means you'll be very weak early on, but in the later chapters you'll have game-breaking spells, like the one that kills any undead instantly, the one that summons a demon (a monster which is one of the toughest enemies in-game) or, worst of all, the area spell that will kill any enemy in 2 hits (except the final boss, it takes 3 casts instead).
When I played a mage (with NotR installed, it may be different with only the basic Gothic 2)
I seemed quite clear to me that the game was NOT meant to be played as a mage and was not balanced for it.
So I would say that most of the OP's problems stemmed from playing a mage and having NotR installed. I'd highly recommend playing a fighter or archer type first instead.
Oh, and to be clear, I did enjoy Gothic 2 very much, mostly because RPGs that are actually hard are so rare. It just isn't a game that's well-balanced for mage characters.

I'd have to agree with mystral: the game is not really balanced, since a beginning mage will have relatively limited offensive power compared to pure melee classes and later on they become veritable powerhouses. For this reason one tip I can give is to buy some dexterity and learn to make Dex potions as soon as possible: you will end up with a hibrid mage/rogue, but at least bows will be a reliable source of ranged damage and there are a couple of swords that are made for Dex-centric chars. After that dump most of your skill points into Mana so that you can cast more spells before having to down mana potions. Also I suggest reading a few guide on gamefaqs for extra info, other than the following thread: http://www.gog.com/en/forum/gothic_series/gothic_2_new_player_tips_and_help.
Also Fireball and Lighting are going to be the main "attack spells", since they have the best damage/mana ratio. And Ice Block is a life saver, along with summon scrolls/runes.
Personally I love playing as a mage, even with NOTR increased difficulty, since they get more of the background story, and I like some of the side quest (but this is personal preference, so feel free to disregard). And there are few things as satisfying as having to suffer through the game and then having access to the best spells in the game, walk in the middle of the orcs surrounding the Old Camp and blasting all of them with a single spell. I don't know why the paladins were so worked up about the Orcs, since I managed to clean them all out in 10-15 minutes. :p

Note that Dex-based swords are only an option with the Night of the Raven add-on installed (which is the default for the GOG installer). If you are playing the original Gothic II you will have to go with something else.
Also note that Dex-based sword critical hits are still based on Strength, not Dexterity, so you need some Strength even if you are going to use Dex weapons exclusively. Spending extra LP on Strength isn't recommended if you aren't actually focussing on that attribute, so you will want to focus on brewing/buying Strength potions, reading Strength tablets, etc. If you feel you can spare a few LP you can get a lot of Strength by learning how to brew the potion and saving your Dragonroots for that rather than eating them raw (which has a weaker effect). You can get maybe 20 Strength from alchemy alone.

Nothin I said is untrue. The magic system means you won't be all powerful, raining death down upon everyone (well, the final circle spells are pretty overpowered but by the time you access it thre isn't much of the game left)
I've played through both games (NotR) as mages
Of course, I supplements with skills in 1h and bows.
You have to use your brain, your items, and your other skills. But you CAN deal huge damage and take down the "boss" like characters quite easily with a mage

I played Gothic II NOTR as a mage and it is very UNbalanced (edit a typo that changed the meaning) :
- The game is horribly hard at the beginning - all your first spells are weak and / or resisted, and you will have a lot of difficulties killing the black robe dudes, or even a single orc. I spent most of the first part of the time dodging enemies, shooting them from above or pulling them on guards. It is really extremely hard. I advice you to save the summon demon scrolls for the dragons. (2 or 3 of them are necessary).
- Once you reach the point where you can summon demons and cast the "rain of death" spell (whatever it is called), there is no more difficulty whatsoever. You cast the spell, the enemy is dead. It is that simple. Even the final boss why way more easy to kill for me than a regular orc mid-game.