Here is my idea, and I think it will greatly increase the realism (and annoyance) in the game. It is the addition of the deflection setting in court.ini. This is what I mean by deflection: sometimes the ball will hit an odd spot on the court and bounce in a different direction. You should be able to turn this on and off in the advanced options under the misc options menu (maybe when you are making a multiplayer game, as well?).
So, that's my first idea. Any opinions here?