An interesting thread popped up over on the Fires of Heaven message boards about the greatest MMO features that never got copied. The list includes some very cool stuff -- such as vendors storing items sold to them, allowing other players to buy the items back -- as well as the deity / alignment system from EverQuest, Final Fantasy XI's all-jobs-on-one-character mechanic and auction house system, World of Warcraft's User Interface mod-ability, and a whole lot more.
What are your thoughts on this? What are some of the features you've noticed from MMOs in the past that were extremely cool in your eyes, but haven't been adopted by the genre as a whole?