Why did they remove the hero specialization?!! This deprived the heroes of their individuality, which was so pleasing in the third game.

What is hero specialization? :) And in the third game, there are many heroes with the same specialization. For example, in the fourth game, you can create a hero with the Assassin specialization; I've already written about it somewhere. All his weapons are poisoned, meaning that when he attacks units with a sword or arrow, the Poison spell is applied to them, even if the hero doesn't have that magic yet. Moreover, the player doesn't immediately get a hero with this specialization; yes, they are almost all the same at the start in the tavern, but the player creates a hero with the desired specialization from the available material in the tavern. So, what's wrong with that? It's even more interesting, and you don't have to bother searching for the right hero as in the third game.