How about this...make it possible to "attack" clan mates, so they can check to see how their defenses are and get real life feedback on where to strengthen their bases at. This could also benefit clan wars, as clans can see which base to mimic before the war begins, kind of a mini tournament type of thing.
What's at stake? Again, clan contests and pride of knowing you have the best base layout/army strategy in the clan.
Mode can be turned on and off or challenges can be made by friends...come on, who doesn't know someone or has got someone they know to at least try this game...standing next to them could make for some fun times with this feature.

