The idea of making small monsters stronger is exactly what is needed! I am all for it!
I hope I understood the word "small" correctly.
The problem is that in the third game, there were UPGRADES. A disgusting, annoying feature that doesn't add anything useful to the game.
Because of these upgrades, there were a lot of problems: Necromancers couldn't turn skeletons into skeleton warriors (because the "Necromancy" skill only made regular skeletons, which, without a special slot in the army, simply disappeared). For example, you find a squad of 500 Gnolls. And you have to think - either discard your 400 Gnoll Marauders for them (and then pay money to upgrade these five hundred to Marauders), or miss such a great opportunity to replenish your army.
If this function didn't exist, the number of different strategies and tactics would be halved