What would you change in Heroes of Might and Magic IV?

I believe this isn't nonsense, but a unique feature of the game. An important feature that the third and fifth installments critically lack. For example, you're exploring the adventure map in the third game. You encounter 400 Minotaur Kings. And – what a surprise! They decide to join you. And then you frantically think – should you discard the Harpies (and lose the ability to quickly and easily deal with small groups of neutrals), or discard the Angels, which you collected in five Conservatories one by one, or maybe get rid of the five hundred Pit Lords that joined you a month ago... In the end, you discard one of the useful, necessary units, and take these damned Minotaurs. No less useful, necessary, and powerful.
Question: why discard anyone at all? Where is the logic, where is the playability, where is the meaning, in the end? It turns out that if a diplomat hero has gathered an army of his city (all seven levels of creatures), he must prepare in advance to discard various parts of his army during the game? That is, the money spent on the creatures is doomed to be wasted. Or should he leave the least useful creatures in the city in advance (which reduces the "meat" and lowers the chance of neutrals joining him) in the hope of replenishing the unit with creatures of other races.

Troop movement without a hero, their gathering of resources, setting up "guards" designed to keep the fog of war open on the borders of the kingdom – this is correct and logical. After all, in the fourth game, troops without a hero cannot capture a mine or claim a foreign city as their own (even if they kill all its guards) – and in the end, in the fourth game, troops are an order of magnitude weaker than heroes. No one will ever FIGHT with hero-less troops.

After all, in the fourth game, troops without a hero cannot capture a mine.