The question might sound like it has nothing to do with UE, but it does, because generally optimization techniques used in one engine/programming language, can be applied to other engines.
So, if you have played M&B, chances are you have seen battles of more than 300 NPCs, where each individual NPC is pretty smart. Well maybe not genius, but it still does calculate some things pretty well, such as whether to move or attack, how to attack, react to commands and groups, etc…
In my mind, even moving so many 3D NPCs would be problematic (not hard to implement, but laggy).
How can such a system be optimized, without making NPCs dumb?