What is your opinion about Heroes IV?

Night
Daily increase – a successful/unsuccessful one, but it makes sense, slightly changing tactics and strategies.

What kind of common sense? Is a separate trainer assigned to each "recruit"? A weekly increase is more realistic (at least for low-level units): they gather a group of "recruits," train this group, and add them to the army.

Added 17 minutes ago

Maybe it's because the creature compositions in the Castle factions in the fourth game largely repeated those in the second game, rather than the third game, which mixed everything up?! Oh yes, now the favorite argument of the fans of the third game is – "Orcs" for the "Chaos" faction, what a horror – but you won't find more obvious mistakes. In terms of "completing" the Castle factions, the fourth game corresponds well to the true classic – the second game.

And in the fourth game, there are demons and necromancers in one Castle, elementals for the Elves, and a griffin was in the second game for the Chaos faction. Also, the dragon golem for the Mages on the last level – it's just :D.

Added 11 minutes ago

"inconsistency with the series" – what is that?! Maybe it's because they returned to the traditional – classic – system of six Castle factions, which appeared in the second game, which was interesting and well-balanced, and which was later destroyed by the "ideologically" absurd nine Castle factions of the third game and its add-ons.

Heroes fight – was that the case in the second game? Can there be more than one hero in a squad – also from the second game? The skill system is from the second game? In the second game, did the siege of a Castle take place without a catapult, and simple units break down the gates? Similar races and spells – that's all the similarity between the fourth game and the second game.
The fourth game cannot be similar to all the previous parts (but this does not mean that it is an unsuccessful experiment), because it is a mixture of Heroes 2, Age of Wonders, and Disciples.

The fourth game is a worthy game, but not a continuation of the classic Heroes 2.