I would like to experiment with an MMO that is 99.9% player driven. Towns are not populated with homes belonging to a random NPC, the house belongs to a player, home to treasures and rewards of his conquests. Also, I would have it have a PvP thing where its not just battles, its like you can commit crimes. I would like to imagine spending an afternoon tailing an impressive looking high-level player with some friends, casing his house, and the second he leaves for a quest me and my friends sneak in after lock-picking and ransack the place. Of course this kind of thing is level moderated so a level 80 cant take the hard-earned spoils of a level 10, but Imagine the feeling you would get, returning to your home and noticing that the sword you just bought and stored in a chest beside your bed went missing. another thing I would like to implement is a CSI style thing that you can use to track down the kidnapper if he made it really obvious. Aside from that, it would be First person and play like oblivion, with some impressive hand to hand combat and executions, since I am a HUGE fan of executions.