This was posted in general chat by san-mpq and it sounds like a great idea.
Allow all covers to expire, according to the 
rating.
expires in 1 week
expires in 2 weeks
expires in 3 weeks
expires in 4 weeks
expires in 5 weeks
This is reflective of the difficulty of championing them. Four star characters who are even remotely close, CAN be championed in 4 weeks or less by an avid player. This is fair, no?