People calling for a 12 team playoff are nuts IMO.
I would much rather keep the playoffs at 4 and let the other teams continue to play in bowl games. Who wants to watch teams like MSU, Wake, ND, etc. play a top 1-3 team in a playoff game and get rolled by 5+ TD's?
It would be much better for them and for the fans for them to be playing in a major New Years bowl game against someone else who has a similar talent so they have a chance for a win or at least a competitive game. If I were them I would much rather finish the season with a bowl game win vs getting blown-out in a playoff game.
If it were me I would leave it at 4 teams or maybe 6 teams. The regular season needs to mean something and the playoffs need to be competitive.