MMH5.5 - Heroes of Might and Magic 5.5

I also don't understand why create so many classes when 2 per faction is enough. A larger number is no longer diversity, plus it reduces the uniqueness of the faction.

I strongly disagree. Two classes, in my opinion, is very few and boring, especially it becomes obvious when I try to install some other mods after this one. For me, such variability is one of the main advantages.
And it's not difficult to add hero models from other mods manually).