I dislike how everyone says werewolves are mindless or can't be controlled I mean couldn't you become one in Daggerfall? So couldn't you control your character when you were one? Hirulin (??) wasn't involved than was he??
Either way they could make up a new way for werewolves to be playable and controllable some way or another like maybe we never killed him back in Morrowind and he somehow lived on or it wasn't really him? He said he'd be back after all:)
In most sources of werewolf fiction they are depicted as having no control from their human side. Would most people instantly start murdering everyone around them if they still had control? The reason this doesn't impact gameplay is because it's not fun for the player to have control taken away from them, especially if it's going to be a long time like the whole in-game night. Having a kill quota was a way to simulate that lack of control, that you "have" to kill someone.
That aside, I prefer to think of them as mindless, psychotic beasts because I think it makes them more interesting. If they have full control, they're nothing more than another beast race like Argonians and Khajit. If they have partial control, they're just another animal in the woods, about as remarkable as regular wolves. The madness means you can't reason with them, can't frighten them off like an animal or count on their instincts, or even make them hesitate with pain. The ferocity of it sets them apart from other creatures.