I'm not sure if this is an entirely possible suggestion, or if it's even a good one because there would be ways to abuse it, but I really would like to see a setPlayerAvatar output for the events.
For example, you walk over a brick and your appearance is changed to a preset avatar done with some kind of gui. I'm not exactly sure how it would all be done.
Just a little suggestion that, in my opinion, would be neat to see.