Heroes 5.5 WarGame Edition - Tactical Edition.

Still, if the skills are all okay now, the stat distribution across classes can still be improved.
The main principle here is this: each race has one primary stat and 3 secondary stats (1 for each class).
Humans, Dwarves - primary Defense.
Demons, Orcs - primary Attack.
Elves, Shadows - primary Spellpower.
Mages, Undead - primary Knowledge.

Accordingly, for each class there is a pair of profile stats (with a drop chance of 30-40%), one of which must be primary for the race.

ATTACK + DEFENSE
Knight (humans) = 30/40 + 10/20%
Warrior (dwarves) = 30/40 + 20/10%
Overlord (demons) = 40/30 + 20/10%
Barbarian (orcs) = 40/30 + 10/20%

Obviously, 40% defense should be given to humans and dwarves, while it's logical to give 20% spellpower to the chaos factions (dwarves and demons). That's why there's this specific distribution.

ATTACK + SPELLPOWER
Huntress (orcs) = 40/20 + 30/10%
Ranger (elves) = 40/10 + 30/20%
Fiend (demons) = 30/20 + 40/10%
Assassin (shadows) = 30/10 + 40/20%

Obviously, 40% attack should be given to the physical classes—the Ranger and the Huntress—while it's logical to give the minimum 10% defense to the most fragile races (elves and shadows).

ATTACK + KNOWLEDGE
Reaper (undead) = 40/20 + 10/30%
Destroyer (demons) = 40/10 + 20/30%
Shaman (orcs) = 30/20 + 10/40%
Mystic (mages) = 30/10 + 20/40%

Obviously, 40% attack should be given to the physical classes—the Destroyer and the Reaper. Furthermore, between the Reaper and the Destroyer, it's logical to give 20% defense to the Reaper (the most combat-oriented undead class), and between the Mystic and the Shaman—obviously, the physical stat (20% defense) goes to the Shaman, while the Mystic should logically focus on spellpower (20%).

DEFENSE + SPELLPOWER
Inquisitor (humans) = 20/40 + 30/10%
Avenger (elves) = 20/30 + 40/10%
Priest (dwarves) = 10/40 + 30/20%
Witch (shadows) = 10/30 + 40/20%

Obviously, 40% defense should be given to humans and dwarves, while it's logical to give 20% attack to the more combat-focused Inquisitor and Avenger.

DEFENSE + KNOWLEDGE
Veteran (dwarves) = 20/40 + 10/30%
Paladin (humans) = 10/40 + 20/30%
Alchemist (mages) = 20/30 + 10/40%
Necromancer (undead) = 10/30 + 20/40%

Obviously, 40% defense should again go to humans and dwarves. Between the Paladin and the Veteran, the Paladin is a more magical class; therefore, his spellpower should be 20%. Between the Alchemist and the Necromancer, the priority 20% spellpower logically goes to the Necromancer because the Alchemist is the basic combat class for mages.

SPELLPOWER + KNOWLEDGE
Druid (elves) = 10/20 + 40/30%
Archmage (mages) = 10/20 + 30/40%
Warlock (shadows) = 20/10 + 40/30%
Cultist (undead) = 20/10 + 30/40%

Obviously, 40% spellpower should go to the elven races (Warlock and Druid, who should not be inferior to the Avenger in spellpower). At the same time, the Warlock is more aggressive than the Druid (20% attack vs 20% defense), and the Cultist is more aggressive than the Mage (20% attack vs 20% defense).

Now, the stat distribution seems ideal. Leave comments if you disagree or have alternative suggestions.

Regarding the Huntress (orcs), I'll add that I've reconsidered my views on the effectiveness of spellpower for orcs. I think that magic resistance can be removed from the progression and built in as part of the orc racial traits (this technical possibility exists). In that case, no "side" stat bonuses would be needed, which were proposed initially (converting spellpower into other random stats). Since there's a 50% spellpower penalty (which isn't boosted by orcs, but is boosted by other races through magic school progression), this should theoretically be enough.

Added 1 hour 42 minutes later

A high defense stat is not an indicator of survivability, unfortunately. There is magic, there is partial ignore, there is the ballista. There is Orson with a wild amount of meat in the early stages. And it is exactly this meat that provides him with the necessary number of casts, not the defense of the Dancers. And not the archers, but the Warriors.
Warriors are many times more effective than archers at breaking through. Tested, don't argue.

In the original, they dealt more damage; in WGE, elves as a race are categorized as RusherTanks (high initiative with low damage). Now, under buffs, he certainly won't be weak (elven classes have huge spellpower), so an elf must definitely rush Light.
That is, you will need to level up not only Logistics but also Keen Mind for the hero to manage to cast the double/triple damage buff on the dancers (with 8+ spellpower), and then it will be dangerous.
Otherwise, half-naked guys with knives who move often are unlikely to be able to deal critical damage on their own. The exception is the blue guys, who can hit T7 units quite hard (ignoring defense via charge), but that's only one target.

Really high damage will be concentrated in these races:
- orcs (high damage, low initiative)
- demons (high damage, low survivability)
- undead (low initiative - consequently, high power)

And if we consider turn frequency (number of attacks), we can also add:
- shadows (high initiative, low survivability)

As for the question of archers vs warriors, in the original PvP, skeletal archers were very weak. With normal archers, warriors would never have been taken for the breakthrough.
If an archer is normal in PvP, then in PvE it's an overpowered unit, precisely because of the minimization of losses; there's no point arguing here, it's obvious.
In MMH5.5, for example, to partially fix this, they raised the HP of all units; I definitely don't like that solution because it slows down the battle. But directly reducing the percentage of losses during the battle doesn't break anything, yet it cuts the effectiveness of archers. In other words, this is the most effective way to balance PvE abuses.