Positive:
1) Artifacts, potions, etc., no longer clutter the entire backpack by stacking identical items into one slot.
2) There are large units that occupy 2 leadership points.
3) The campaign storyline is quite interesting.
4) Legions, Empire, and Alliance are well-balanced.
5) Information about units remains visible and doesn't disappear when you stop holding down the mouse button, allowing you to view abilities (now they are displayed with a small icon) and other units of opponents and neutrals.
6) Many units, such as hornets or ghosts, have additional effects in addition to damage, such as paralysis, poison, immunity, etc.
7) A menu has finally appeared in battles (I don't remember if it was in Renaissance).
8) The cover system has been improved; it now works not only when you try to attack but also when you simply run past.
9) The appearance of some units' attacks has been changed (for example, the Silent Assassin now throws a blade).
Negative:
1) The Hordes of the Undead are poorly balanced compared to other factions; they are weaker than others at the beginning. Higher Vampires with vampirism, Shadows with mass paralysis, many units have immunity to weapons. In general, they are effective against everyone, especially neutrals.
2) The AI behaves inadequately against the Hordes of the Undead:
For example, a Bone Warrior and a Werewolf are standing next to each other, and the smart AI attacks the Werewolf, which is immune to weapons (it does the same with the Spirit and Death, with disastrous results).
4) Human mages are useless; if you need a mage in battle, you should take a mage hero because the White Mage deals 100 damage, and considering that mages have low initiative, the mage won't be very useful. The Elementalist deals 60 damage and is even worse than the White Mage due to its even lower initiative, and its elementals are also useless.
5) In the inventory shop, there is no sorting of inventory by hero or at least by faction; everything is just thrown together.
Bugs I noticed:
1) Wind and Fire Maidens do not provide immunity to magic along with healing, and not at all.
2) In the Castle of the Hordes of the Undead, there are only Alliance unit summoning runes, although there should be runes for all 4 factions. The same problem exists for the Legions.
3) In 2-3 single-player maps, if you attack an enemy castle, victory is guaranteed even if your army loses.
4) Instead of Mizrael in the capital of the Empire, there is a Border Guard.