I look forward to the day where "scripted" characters can grow and learn. Characters with certain tendencies and traits set by writers can grow and learn in different ways since they are weighted differently and have different goals. Think the AI in S.T.A.L.K.E.R, but more "organic".
One thing I'm interested in is emergent language from scratch within a setting like this. Probably not the best idea to attempt to train a language model on MMO chat logs.