Would be nice if there was some solution to actually run code, so it can be used to pair up and teach or test people. The UI could also benefit from some streamlining (that sidebar takes up a lot of space for info you don't need to see all the time). Also if there's any possibility to share a directory of files to simultaneously work on from one of the user's (or the server's) system. That'd make this a pretty good product in itself.