the attackers would make ladders to put on the walls, the pc gets to kick them down, the attackers would get bigger units (like ogres and dragons, the pc gets to shoot it with a ballista, the pc can go around getting reinforcements, supplies and stuff. the pc could leads hordes against hordes, the pc could build up the castles defenses- perhaps teach how to fight, or to summon daedra to do their work for them,.
alternativeley- if i dont get to defend a castle/ village - could i at least be apart of something epic? like a cavalry charge or a storming of a castle? or simply a 50+ npcs battle?
i also want unique music specifically for epic battles
edit
just to clear a few things up
1: if ai is optimised, a game can get hundreds of npcs on screen without lag
2: i have said nothing about leading battles - leading battles has nothing to do with wanting them or not.