Heroes 5.5 WarGame Edition - Tactical Edition.

Regarding the replacement – it's essentially just a recoloring. The other aspects are much more complex, and creating models from scratch is almost impossible.

Hydras are questionable for this faction. Some kind of spiders would be very appropriate.

Hydras are hydras; it's a matter of taste. Why can't a hydra be an underground creature? Again, I have nothing against spiders (although in Ashan, spiders are logical for the undead), but who will draw them?

Blood sisters and witches are logical, but they are bland and boring. And they don't look good – it's obvious that they were hastily made.

The warrior women are just warrior women. The only thing is, the heels are a bit of a misstep.

Minotaurs would be more suitable for barbarians in general. Instead of wyverns, for example.

Why would they be suitable for barbarians? Don't they have enough similar creatures (orcs, executioners)?

Now, the Tower faction is a mishmash of swamp and dungeon creatures from Heroes 3, plus some kind of mediocre units.

I advise you not to compare it to Heroes 3 in this regard, because the game world is completely different. There, by the way, I also had the impression of a mishmash, rather than in Heroes 5, where in the dungeon, 4 out of 7 units are units of the core race (Tower).

Since the balance is being reworked anyway, it's just a matter of a couple of new models.

As I said, these 2-3 new models are practically impossible.

It would also be great to replace the dwarven dragons. They don't fit and look like generic garbage. And there are clearly too many dragons in the game.

I liked the original version of the dwarven dragon (as in the developers' artistic concept), but unfortunately, there is no such model in the game.

It would be good to replace the death messengers with knights in the necropolis, and put the messengers instead of dragons on level 7. Bone dragons are, of course, a classic, but death messengers are a great replacement for them.

I might have supported this idea before, but not now. Because everyone has their own role. Necrodrakes in WGE are clearly debuffers, while death knights would be more like damage dealers, which doesn't fit the current style of the undead (where damage dealers already exist – messengers).

The mages have some kind of rakshasas. The old, good nagas were much nicer. Or, for example, elementals.

Rakshasas are rakshasas, a perfectly normal alternative to nagas. Why not? But I have a rather negative attitude towards elementals as full-fledged castle units, because they are boring (and poorly drawn in Heroes 5).

There don't seem to be any such colorful creatures as cyclops, harpies, hippos, etc. in the game. Hippos and harpies would look very good for the barbarians.

The cyclops in Heroes 5 performs the role of a hippo; I would say that it even resembles it more than a cyclops. And harpies – well, why are they needed if there are furies?

Regarding the heroes. 6 skills at the beginning is debatable. It turns out that I haven't even started playing, and the heroes are already one-third upgraded. And not with what I need for my tactics and play style. Or will there be an opportunity to choose these six skills or some of them? I understand that diversity is important... but what's the point of all these educations if you're going to cut them down? Also, the dwarven warrior has a low chance of getting leadership, but a high chance for... a death knight. Why does he need it? The necromancer has the battle machines skill, but the death knight doesn't. It's not logical.

It's not 6 skills, but 6 skill branches. And that's a lot, because each branch essentially gives 6 slots (racial – 8). For comparison, in Heroes 3, there are 8x3 slots.
Education is very useful in Heroes 5, but, as they say, if you don't want it, don't take it, what's the problem?
Necro-leadership is planned for necromancers (a minus to the morale of enemies).

And another thought occurred to me. "Defense" now increases the squad's defense by 50%, instead of 30% in the old games. That is, the tactic of retreating, waiting, and so on has been significantly expanded. But the barbarians have been deprived of this, as blood rage does not allow them to defend and wait. That is, the barbarians are somewhat disadvantaged compared to the other races. Is this taken into account? Will there be any compensating bonuses for the barbarians? For example, something like a bonus to attack/speed/initiative for each defending enemy, or something like that.

No, these bonuses will not be. Blood rage is a great skill in its original form, and in WGE, it will probably have to be limited (weakened).

And by the way. I saw your answer to the request to replace heaven with conflux. If this is possible, why not replace the academy with conflux? There are five models in the game, and two more, and that's it. The cities are identical in terms of magical orientation. But conflux is much more specific and interesting than this oriental thing.

I'm not a fan of conflux and elementals, and I don't think it's a good idea to put a pseudo-conflux with a recolored academy castle instead of the academy.