Brett McMurphy of CBS Sports (http://www.cbssports.com/collegefootball/blog/brett-mcmurphy/18938708) reports that the BCS is considering a playoff model whereby conference champs receive autobids to the playoff, but only if they are rated in the top 6.
Had this system been in place last year, #5 Oregon, which won the Pac-12, would have gone into the playoff over #4 Stanford. However, #10 Wisconsin, which won the Big Ten, would have been ineligible, thus freeing up a spot for #2 Alabama.
This strikes me as a reasonable compromise. In this era of conference championship games, a team can win a weak division despite a mediocre regular season, and be one game away from from playing for the national championship.
Last year, for example, the Pac-12 championship game featured Oregon vs. 6-6 UCLA. Suppose the Bruins had won. A playoff featuring the four best conference champs would have taken LSU and Oklahoma State (no issue with either of those), but also #10 Wisconsin and #20 Clemson.
What kind of playoff is it, if the four teams are #1, 5, 10, and 20? That's not an anomaly, either. Weak conference champs are crowned with some regularity. In the NCAA basketball tourney, where they take 68 teams, this isn't an issue. Even after autobids, there are more than enough slots to take everyone else that truly belongs there.
But if your playoff is only going to have four teams, you need to make sure they're four really good teams.
Personally, I wouldn't mind just taking the top four (however those four are determined). It's the simplest system that everyone can understand. But still, one can see the objection where, last year, #4 Stanford would have received a playoff bid over #5 Oregon, even though Oregon won the Pac-12.
Giving priority to conference champs, while requiring them to be in the top 6, strikes an appropriate balance. It gives value to winning your conference, while ensuring that a #20 team can't get into a four-team playoff.
Once you get below #6, you're almost certainly into teams that had weaker seasons, and in a playoff limited to four teams, they don't belong.