Limit on the number of troops per hero.

Question: Why have nomadic and combat units at the same time?

Added 11 minutes later
The troops are divided among the heroes with a specific purpose, not just to make the game more interesting... Some heroes level up magic in order to pass on spells to the main hero, others serve as auxiliary heroes for healing or guarding the city, others defend artifacts to avoid losing momentum in the game, and still others defend necessary mines and passages in zones, and so on... It all depends on the goal being pursued in the game...