I hadn't realized there was anything this severe going on in the difference between hero types. Thanks for pointing it out though. I suppose it's fair, as I fell in love with group slow and resurrection lately. They make a fantastic combo, sometimes letting me get out of a battle with zero losses even after taking quite a beating.
One note though: I think I'm going to stop using the ballista when using warlock characters. If I'm down to one enemy stack I must keep blinded while I move my troops into position or resurrect them, because a battle will end things before I can resurrect enough troops, the ballista becomes a huge liability, shooting every turn and removing the blind spell. Most of what it does that's positive is simply serve as a target the computer things is high priority. But if could keep targets blinded, I could absorb that attack and just resurrect.
Definitely a good tip. I do that too. Generally the only time I don't is when I find gold at the beginning of the game. I start off with a second hero on the very first turn, and have him transfer his troops to my main hero, and then they both go out looking for wood and ore and picking up gold. I generally try to avoid fighting in the first few weeks, until I have built up some money-generating buildings and then upgraded my archer type soldiers.
I also do that when fighting dragonflly hives, imp caches, or other things that tend to give you free troops when you beat them. I'll pass off my worst or slowest troops stack to a squire so I have a space open. Last game I got a big surprise when I attacked some harpies and 218 offered to join me. Heck yeah!

I'm all for the cheese. No wise general wants a fair fight. Go looking for those and you'll run out of men pretty fast and have a short career. I did this a lot this game. Now, playing a warlock and taking mysticism for double spell points, as well as basic earth magic, has become a very cool style for me. Resurrect goes down to 16 points when you hit expert level, and when you have 1200 mana points (by going into the castle and doubling your points with the mana vortex building), you're a perpetual motion killing machine.

Leadership is now a top priority for me. For my new obsession with playing a warlock, it's leadership, basic earth magic, and mysticism above all others. Reluctantly, I'll even surrender the chance at battle tactics for it, which is another I find extremely useful.
My personal nightmare. Great to pass off to a secondary hero who's not a caster, though.
I always try to let a strong secondary, maybe even tertiary, hero develop and get experience. Maybe it would be a good idea to let at least one of those be a melee-based hero, just in case you get that orb. Very tiny chance of seeing it IMO (first time I have so far in almost 30 games), but still a nightmare if you do.
I put together a necro special item last game that lets you recruit 30% of the fallen as liches. Extremely powerful IMO. No time to develop Sandro at that late stage of the game, though. But that would be an incredible artifact to play through the game with.

I assume you meant Intelligence, not Mysticism (one of the more useless skills). Also, if you're going for a more magic than might hero I'd also highly recommend taking Water Magic in addition to Earth Magic, as the mass buffs and debuffs can really help when facing enemy heroes with superior stats. Between Bless, Prayer, Forgetfulness, and Weakness you can really tip the scales in terms of damage output between yours and your opponent's army. Toss in Shield (from earth magic) for even greater effect, and mass cure is quite nice for quickly removing any mass debuffs your opponent casts. Also, depending on whether you prefer to pick off the enemy from afar or get up close and personal it's also a good idea to take either Archery or Offense, as the straight up 30% damage boost is quite helpful.
Heh, Cloak of the Undead King is just plain broken. I used it in one or two games, then never used it again because it just took all the fun out of the game.

I put it together while playing Viking We Shall Go! (and while playing Necropolis) - a XL map. Well, I had several thousands ol Power Liches oneshotting almost everything. My other units were there just because I cba to park them in some town.

Haha! Well I'll definitely have to try it just for laughs then.
Yesterday I played an XL map and got through it in 66 turns. The thing is, the computer put the enemy's starting castle right next to mine. I found a second castle early (more and more, this seems to be one of the key things in how a game turns out) and developed it for money ASAP, then was getting so much money so early that I got an insurmountable lead.
Also, I played it so there was no underground. I always start underground with dungeon otherwise, and I believe that is a disadvantage. Moving far away at all from your castle can become an impossibility if you get held back by just a few tough stacks at choke points. That delay in picking up easy experience and mines and castles early can be pretty severe.
Also, I don't know if this is always true, but it seems that upstairs is where most of the free money/gems etc are. Leprechauns and such don't come downstairs; I only see the occasional wiindmill and not much even of those.
This is especially tricky with dungeon, I find, because you need so much sulfur. If you get few weekly chances of freebies of sulfur, plus find it hard to get around the map because of so many narrow choke points, it can cause quite a delay. I've heard others say this is a weakness of dungeons, and I didn't know if that was being exaggerated. I've come to believe it is true.
Two other things: I did mean intelligence, when I mentioned the mana doubling skill. But I don't find mysticism useless. Restoring your mana without wasting a turn or half turn overnight in the castle -- and most importantly the long time it takes to get back and forth to a castle -- is pretty cool. The mana only comes in dribs and drabs, but then you spend so much time running in this game that you only use it in dribs and drabs too, generally.
One thing I love about playing the dungeon towns is that if you get the mana vortex to double your spell points, and intelligence to double your spell points, you don't have to go home too often or fret using mana like I am used to doing with other types of town. If you get mysticism, you almost never do. Overall, with or without the mysticism, the chance to quadruple your mana translates into a pretty big edge, IMO.
Oh, and the in-house creature generator doesn't suck either. Unless you tag too many creature homes outside the castle; then you could wind up with all kinds of junk.

Are you not finding enough wells in a game to keep you supplyed throughout? I normally find that those with castles when your near them keep your mana supply good without mysticism. Much better things to spend your limited skill choices on.

This is one of the RMG's biggest faults - it can do weird things. Once I have started (and even finished) in a closed valley surrounded by mountains. The fun was, that I had no means of escape from there. I had only sawmill + quarry nearby and I was playing with Fortress (= 3 magic guild levels = zero chance for dimension door. Even if I had 5 more magic oriented castle, there was a big chance I would be screwed anyways).
Another time there was a quite large grassy plain, with 3 subterrain gates next to each other. There was no forest or mountains between them, just open space.
That's why I don't play RMG maps and if anything, I just download some new ones.
Probably the RMG has some patterns and rules about adventure objects.

I don't find wells all that common, to be honest. I'm usually no closer to a well than I am to a castle.
By the way, I don't know if I just didn't notice this before in map sizes "large" and lower -- you get very wide areas in XL (whole terrain types) that have no castles in them. If you're going through them, it then becomes quite a ride to replenish your mana. It can very easily take a week and a half to two weeks of time for a round trip, worse if you're on rough ground. (This is one of the reasons I also like things like pathfinding and logistics a lot.)
Re: taking skill choices, you know sometimes I find myself almost desperate to take something that isn't terrible in case I get offered something that's really crap instead. The game I'm currently playing, I have been holding out forever trying to get leadership and just can't manage it. I keep on getting offered crap instead and maxing everything out to expert while waiting. It's quite rare that I get every one of the few skills I think of as game-changers for my warlock.
The core is intelligence, leadership, and earth magic. I also really love archery, and tactics.
This is one of the things where luck figures in kind of strongly in a game that you wouldn't think would have luck operating on quite that level.
I think it would have to. Can't have shipyards in the middle of the desert, after all. Upstairs gold mines, if I recall correctly, are nearly always in mountains.
I've kind of wondering where the wind would come from to have windmills underground!
Anyway, as great as the game is, and it really is, there are some imbalances here and there.
So far I am still enjoying playing random maps, though, even if the occasional one turns out to be an unfair bottleneck or otherwise a dud. The thing with predesigned maps I don't like is there is generally one way to play them that is by far the best, if not the only answer, and I spend my time not playing my very best game but trying to guess what the designer intended. I like having multiple possible solutions and being able to adapt, rather than being marched down a path.
P.S.: I am beginning to hate dimension door. It is a ridiculously huge advantage to whoever gets it first, an absolute game-changer. Sometimes I feel it's like turning on a cheat code.

That is understandable. BTW as you have mentioned earlier that with Dungeon you always start in underground, maybe that's because of the native terrain for every castle and a cave castle in the middle of snow plains would look.....weird. This was somewhat fixed in HoMM4 so even though the towns didn't like that pretty like those from HoMM3, if you had town in swamp, on the town screen the was on swamp terrain (which was good, IMO).
*cough* *cough* Conflux *cough*
It is a huge advantage indeed, but I think Angel Wings are on par with DD or better (free flying spell for anyone who has the artifact equipped - even might hero with little to no spell points can use it to harass and unleash a guerrilla war). Yes, DD can get you further, but it is quite mana expensive, AFAIK.

Yes it is, but if you have the intelligence skill, you can do it quite a bit. But really even using it rarely is still a huge advantage.
I'm on my 27th random map game since buying HOMM3 and and I've only seen angel wings in the last two. I've seen quite a lot of dimension door, though.
I'm playing an interesting map this time. Never seen one quite like this. An XL map, all above ground, with very few mines, but an incredible amount of gold, gems and crystals and such, and leprechaun ponds and windmills. I filled up on my 8 heroes very fast, just to get as many resources as I could before the enemy got near, and to keep visiting the leprechauns and windmills every week. I think I have like 350 gems and one gem mine.