I think it would be nice if there was some way to get into a running game to watch, even just a spectator mode. Naturally, this would be good with a way to customize the game so that you don't allow kibitzers (or do), which brings me to my next idea.
Along with that, it would be nice to customize the select mode's time.
Third and lastly, it would be nice to have titles like the old game as well (master, intermediate, novice, n00b etc.).
I realize that is hours of programming right there, but they are only suggestions. :)
I like the idea of kibitzing, which has been discussed before, but I don't like the idea of titles as they would promote cheating.