Added 4 minutes later
No one makes it to the late game with them. In single-player, it's okay, but against a decent opponent... You'll only win if you're very lucky, or if you have a lot of skill.
If we assume that you can only attack after three or four months of the game, or even longer... In my opinion, I can only evaluate the strength of a race at its maximum level of development and when all its possibilities are used. Here, I repeat, mages crush everyone...
Added 5 minutes later
For example, an Orc with an army upgraded with minotaurs, each stack of archers gets +40% initiative, and the gremlins also get +16 to HP + mass acceleration spell, and that's it, they're unbeatable.