For me the most important thing is a world that makes sense. Story is there to create the atmosphere.
Story gives reason for actions. Which actions you take should be up to you.
For example- omni vs clans is story driven, and gives reason to pvp.
the player needs to show a bit of fantasy to fully enjoy.
What story shoud not do is to force you into immediate action like quest driven storylines. That way you are forced into behaving a certain way and exactly follow a certain path. Thats like a bad movie.
the player doesnt need to think at all. ideal for dull players.