I would be interested in a playoff up to 16 teams. If smaller conference schools have a shot at a national championship, things get exciting.
I enjoy pulling for the underdogs, which is why March Madness is so fun to watch. The way football is set up now, you will never see a George Mason/Butler-like cinderella run. Sun Belt, MAC, WAC, etc schools have nothing to play for when you look beyond a meaningless conference title and a trip to the prestigious Famous Idaho Potato Bowl. I know a small school will rarely will have a magical run at a title, but I don't like the idea of counting a school out just because of their conference. If they win their conference, give them a shot.
This would greatly even the playing field. All 120 schools have a chance at the national championship. I think it's laughable when you consider how it is now, only 66 teams have any sort of chance. Excluding almost half of the nation's schools from a shot at the championship is just plain wrong.
Every school should have a chance, give every school something to play for. That's my opinion, anyways.