I'd like to be able to see how my clan performs against another.
I can see in "my performance" how I'm fairing personnaly against any particular player I've played. A similar tool for clans would be great. (I'm talking about regular challenges, not just league play)
That would do a lot to foster rivalties especially if everyone can see this!
(It would also make it easier to find a particular challenge when your clan is very active and challenges get spread on many pages)