well you are right, but the ai possibilities can be endless,its an interesting subject of debate, but for rpgs i think it has to be based on the intelligence of the mob, lets say that a animal type mob just need to have 3 types of rutines, one for randomly moving around the map, another one to choose better target, or just nearest target and attack, and another one to flee from combat if the enemy is too strong. this will be a basic primitive ai.
so humanoid mobs can work together against you, as long as they are from the same faction, heal themselves protect their archer/mages, or just run away from combat.
also there are mobs with routines, so they go to work at a certain hour, then after wok maybe they goes to the local inn and then to sleep in their houses, like oblivion. but this its just a fancy ai.