How many factions are there?

I believe that the most important thing is the atmosphere of the game. The stories of each creature, the alliances between races, the legends of heroes, and many other things that allow you to immerse yourself in the world of heroes. And with each new race, this world is expanded and becomes even more interesting. I especially enjoy thinking about the global coexistence of races! Of course, there needs to be a limit, and I agree with the idea of 10-12 races.
You're wasting your time discussing parameters; Heroes is not just a set of numbers assigned to creature names. It's about fantasy, and without it, it's better not to play the game at all. By the way, similar parameters are the main part of the game's balance, and the difference between units lies in their abilities and legends!