The whole risk shots thing is kind of annoying, what I mean is having a rule about them. It's actually not that hard to return risk shots decently... of course that's because my character has the return risk shot skill, but still. I'd really prefer to use our own custom characters, to make it fair or whatever we could say that the maximum height is 6'5" and minimum is 5'6" or something, just put some basic parameters and hope people can follow them.
If you wanna have a rule about risk shots then it should be risk shots are only allowed on the serve. I think drop shots should be doable at any point though.