About to finish MM6 and start 7. First time playing but have been doing a lot of reading. I'm thinking about going with Thief/Archer/Cleric/Sorcerer. I did K/A/C/S for 6 and it's working great. I'm leaning toward thief for my meathead so I can beef up disarm and not have to worry about it. I figured I could treat him like a knight as far as stats, and allowed equipment, and he should hold his own. I know the big selling point for knight is the shared life thing but honestly I haven't used it once in 6. I'm sticking with the archer because I love having one and am looking forward to playing an elf again. The cleric and sorcerer because they are the best at what they do. (GM spells) I would appreciate all thoughts and criticisms.

All the truly necessary bases are covered. One thing to note is that honorary promotions no longer count toward skill masteries. They're now governed strictly by your own class promotions. There's also a plot branch that will significantly affect how your party develops later on.

First and foremost, the party is functional. You're swapping the Knight for an Archer, which means a bit more Bow-based damage potential, but less melee damage potential. The Archer isn't as durable as the Knight, but they do offer backup Elemental magic. You won't be using any of the Plate armor you find, instead doubling up on Chain.

Your cleric will end up being your Repair Item person, and stuff WILL get broken, so don't entirely neglect the skill unless you just really like paying repair costs. This will drag down the Cleric's available skill points, but Cleric and Sorcerer will both have either Light or Dark, so the Sorcerer can pick up some of the slack there.

as much as I'd like balanced parties to be good, I'm pretty sure going all out on ranged or melee damage is just better. mm7 is pretty good for this as well since you can get all your important melee buffs with a sorc if you're playing light path. I do also enjoy the 3 archers setup just for how broken it is despite how boring the gameplay is.

I'm actually swapping the knight for a thief. Kinda like the fighter/thief of D&D fame. Light armor, sword and dagger, plus all the thieving stuff. Don't plan on addressing spells till after he's built for combat. Probably won't even be needed by that point. All the strength, endurance, and accuracy he can choke down. Will this concept of a uber thief work as a viable main fighter?

tl;dr: The Thief is a viable melee damage dealer. The archer won't be nearly as good in melee as the knight, but the archer does get double arrows per shot when using a bow at Master skill level.

Lots of words:
The default MM7 party is Knight, Thief, Cleric, Sorcerer, which is why I said you're swapping the Knight for an Archer. Speaking of which, one thing to specifically mention is that skill mastery in MM7 and 8 is hard capped for each class. So if you want Grand Master Disarm Trap, you have to take a Thief in your party. You've probably already noticed this, but I'm saying it in case you haven't.

The Thief is a good warrior, but he isn't a Knight. I've attached screenshots of the stats and skills for a Knight and Thief from an end game save (the party's next task is going through the final dungeon), but there are some things to keep in mind when looking at these numbers.
1) These numbers include end game equipment. My gear gives plenty of stat and skill bonuses, like a +17 to Armsmaster on the Knight and a +13 to Armsmaster on the Thief.
2) These characters are only level 38. They have enough experience to reach level 72 (which is around where you should expect to be by end game), which is another 300 some odd skill points to spend.
3) The Thief has a ring giving +15 AC; his AC without that ring is 94.
4) While the Thief has pretty much reached the pinnacle of his skill mastery, the Knight is missing GM Sword (at least 10 extra AC), GM Spear (at least 10 extra AC and 3 extra damage), and GM Body Building (worth nearly 200 more hp at level 36). If I were to advance each of them as much as is currently available, the disparity would grow.

All that said, the Knight is the epitome of melee brutality, the top of the line in raw melee damage and tanking. The Thief is still a good warrior, and he is able to hold his own among his peers of Knight, Paladin, Monk, and Ranger.

I'm afraid my only save with an Archer had some serious anomalies from how I usually play (party was Knight, Monk, Ranger, Archer, which means max Expert in Self magic, max Master in Elemental, and no Light/Dark), or how I'd expect a first time run to develop (my monk used a sword all game, my archer only reached Expert in bow!), so I won't post those screenshots for comparison.

Truthfully, ANY party can clear this game with patience and clever tactics. But if you're looking for THE definitive "best" party then you're looking for three Knights and a Cleric.

For your Knights:
The Arms master skill is the single most operpowered skill in the game. Getting your Knights to Master in Sword skill (so they can wield two) and dumping every other skill point into Armsmaster will have you shredding enemies that chew through lesser parties. Take your Plate skill just so you can wear the plate; don't worry about adding points into it until you have Grandmaster Armsmaster. Take bow skill just because it's nice to have and bows can sometimes add minor Stat boosts. Prioritize your promotion quests, they are all EASY with this party.

For your Cleric:
Mace, Shield and Chain are essential to have but ignore them for putting points into them, you have higher priorities. This Cleric has two jobs: Buff your Knights and keep themselves alive (your Knights will need very little help). Body and Spirit magic should be prioritized but don't neglect Mind. Bless and Heroism should always be active on your knights, and then Regeneration when you get it. Don't worry about combat capabilities, your Cleric won't need any.

But what about traps? Isn't disarm important?

No. Your cleric will be the only one at risk. Clear our a dungeon before opening the chests, then simply rest in the dungeon if your cleric gets KO'd. Your knights can handle any encounters while resting. Take Light magic to buff stronger and faster and to paralyze any particularly nasty foes (titans), or take Dark magic for Pain Reflection and whatever damage you feel needs adding over the absolute mayhem your Knights will be wreaking upon your hapless enemies as they flee before you. Your only problem will be affording all the level-up training costs.

Bah. Elemental magic reigns supreme in M&M.

Why walk from place to place and stick pointy things in critters when you can teleport, fly and rain fiery death on them.

That sounds like an awful time for everything except "Hold A to Melee" situations. No Torch Light, Wizard Eye, Jump, Fly, Invisibility, Water Walk, Enchant Item, Town Portal, Llyod's Beacon, or Stone to Flesh. No Feather Fall until Light Expert, or at all if you go Dark. Using just swords and spears, instead of a wider variety of the best stuff you find. Ew.

Shreds monsters in melee (except oozes), I guess. Make sure you get life drain weapons for all the Knights.

It has disadvantages, yes. But 3K1C is the definitive strongest party. Magic is stronger in vi, might reigns supreme in vii. Magic is obviously still incredibly valid, and I definitely encourage anyone who enjoys the game to try it each way at least once. If you're tired of using invisibility to get around everything difficult, try might :).

As for getting around, a Wind Master and Gate Master can be pretty easily recruited in Avlee.

I respectfully disagree about it being the strongest. I'll agree that it hits the hardest in melee, but that's all it does. I've done a very heavy might run (KMRA), and I did not particularly enjoy it. All the healing, travel, and utility spells make life so much better that I will happily sacrifice the extra melee power forevermore. Heck, other parties can "Hold A To Win" just fine while still keeping that utility; I've done it.

My invisibility is typically limited to areas or places where I can't be bothered to fight my way through the monsters, like Land of Giants, Watch Tower 6, or all the Dragon Breath and Pain Reflection in The Pit.

I've also done the "Hunt for a X Master hireling" routine, followed by "find my previous general purpose hireling" routine. It's annoying; I'd rather buy/find the Fly spell once and keep all the extra gold. Same with portals. Same with Wizard Eye. You get the idea.

triple archer is simply better than triple knight, you need less skill points to get strong and you get just as strong but at range. you also still get all the utility spells outside of beacon (which is cheating anyways).

also I think if you max out skills thieves actually have higher dps than knights (not that this would ever happen) but there is a tipping point at some stage.

In all games I play "wood elf 'heavy' ranger", and I don't like the easiness of magic but I still like hybrid classes,
so my squad in MM7 is elves only, with Ranger, Archer, Paladin, Knight:
all can use the bow and my Archer and Paly may be my quite Mage&Cleric, and the Ranger be my quite Thief.
I mainly fight with the bows (real time, often hitting enter for t/turn aiming), but I'm not scared about contact fighting (t/t).
I find my fun in this challenge.

None of this is true in any regard. Armsmaster doesn't buff bow damage; my Knights all hit for 80-120 damage per action, never heard of bows hitting that hard. Thieves attack quickly but two daggers without GM armsmaster bonuses simply cannot hold a candle to two swords with GM Armsmaster.

dagger hits much faster than sword, they gain +180% damage from dagger skill and are only missing out on half the effect of armsmaster. if you do the math you will quickly see that at maxed out stats thieves out dps knights.

as for bows, yes swords hit harder, bows hit twice so half damage on bow = sword dps. while technically the sword does out dps the bow the bow kills the enemy faster since you won't have to walk up to them. not to mention of carnage practically doubles or triples your damage while facing more than one enemy.