Guild Wars 2 has life in its NPCs, its dynamic events, and its not so repetitive quests. Yes you kill mobs in most of them. But you are working towards something. If you don't defend the keep from the centaurs, they over take it. When they overtake it, you must overtake it. Not as easy as it seems unless you have atleast 7-10 people doing it and even then it can be hard
Sounds exactly like besieged. FFXI had this, and you can be sure that XIV will probably do it eventually (e.g. after 2.0)