To my knowledge, generals being a requirement and leading a group of units, or a retinue, has been a somewhat recent development decision. I remember the older games (Rome 1, Empire maybe?) only had units that made up an army. I can't remember if the first unit in the army was a "leader" or not, but the point is, I used to have so much fun creating custom battles (scorpions against peasants, elephants against catapults, whatever), and seeing how it played out. Now, I can't really do that. There's always an enemy general, and in the case of Three Kingdoms (records mode), he's always accompanied by cavalry.
Is there a mod that would allow me to test units out in custom battles only? Or if that's too complicated because a lot of the game code revolves around retinues, at least disable the enemy general's AI during the battle?
I'm a programmer but with full time work and kids I don't have much time to be developing mods, but I'm half tempted to make this myself. I haven't had any luck finding a matching mod. The Warhammer games had "no lords" mods to handle this, I believe.