If college football instituted a playoff system, it would need a few things (among others) to work.
1. Automatic qualifiers. I know a lot of people hate this, but without automatic qualifiers, there is no playoff (or BCS or any other championship format). That doesn't necessarily mean that any of the mid-major conferences or the Big East must get an automatic bid, the way they do in basketball. But if you do not guarantee a spot to the champions of the SEC, Big Ten, Pac-12, Big 12 and ACC, those conferences will probably choose not to participate in a tournament, the same way the SWAC and Ivy League don't participate in the FCS tournament (though they do it for different reasons).
2. Byes. Specifically, byes given to conference champions. This keeps emphasis on late season games and conference championship games. In a 16-team tournament with no byes, teams like LSU have little incentive to win their conference championship games, which make games like this week's LSU/Georgia match-up mostly meaningless (not that they still wouldn't play their hearts out). But if you have a 12-team tournament and give byes to the top 4 conference champions (or independent teams, if ranked high enough) that makes every game, especially conference games, a little more important, all-be-it not as cutthroat as the current one-and-probably-done college football season. If there were a playoff, this would help college football more than it would hurt it. I can imagine fans of Alabama this year or Stanford this year or last not liking this. But admit it: if your team were in the conference championship game, you'd rather it be for a bye than to have very little meaning.
3. A way for non-AQ teams to qualify automatically. Without it, they'll just take their gripes to Congress again. I propose giving the best non-AQ conference champion or independent team a bid if they finish in the top 16. Give the 2nd and 3rd best team a spot if they finish in the top 12. In a 12 team tournament, those teams deserve a bid, since they can't earn one by simply winning their conference. Most years, this would give a spot to one or two teams.
4. Bowl involvement. A tournament shouldn't usurp the bowls, it should supplement them. No bowls=less corporate support=less money=less support by university and conference presidents. To have support for a postseason change, you need to include the bowls one way or another. Make the first round games four non-BCS bowls and schedule them the week before Christmas. Make the four BCS bowls the second round games and play them two weeks later on or around New Year's (giving the student-athletes a short break for the holidays). Give the bowls the freedom to choose who they want in their games, and let them have one conference tie-in (or two, for the Rose Bowl). But construct the selection process so that the match-ups are generally "tournament-like" (i.e., higher seeds generally play lower seeds).Play the semifinals on neutral sites the following week, and the Championship Game a week after that. This only extends the season by a week and gives two weeks of build-up for both the first and second round bowl games, which ought to keep the bowl organizers happy.
Using the final BCS rankings, here is what this year's tournament might look like. (I chose the first round bowl sites out of preference. A lot of other bowls would be suitable. Take your pick).
Chick-fil-A Bowl - #15 Clemson vs. #6 Arkansas
Capital One Bowl - #2 Alabama vs. #11 Virginia Tech
Cotton Bowl - #8 Kansas State vs. #9 South Carolina
Holiday Bowl - #4 Stanford vs. #7 Boise State
Orange Bowl - TBD (Clemson, if they win the Chick-fil-A Bowl) vs. TBD
Sugar Bowl - #1 LSU vs. TBD
Fiesta Bowl - #3 Oklahoma State vs. TBD
Rose Bowl - #5 Oregon vs. #10 Wisconsin
Last year might have been:
Chick-fil-A Bowl - #13 Virginia Tech vs. #9 Michigan State
Capital One Bowl - #6 Ohio State vs. #11 LSU
Cotton Bowl - #7 Oklahoma vs. #8 Arkansas
Holiday Bowl - #4 Stanford vs. #10 Boise State
Orange Bowl - TBD (Virginia Tech, if they won the Chick-fil-A Bowl) vs. TBD
Sugar Bowl - #1 Auburn vs. TBD
Fiesta Bowl - TBD (Oklahoma, if they won the Cotton Bowl) vs. TBD
Rose Bowl - #2 Oregon vs. #5 Wisconsin
*#3 TCU would receive the 4th bye, but wouldn't be assigned to a particular bowl.
And 2009 could have been:
Chick-fil-A Bowl - #9 Georgia Tech vs. #10 Iowa
Capital One Bowl - #5 Florida vs. #11 Virginia Tech
Cotton Bowl - #12 Louisiana State vs. #8 Ohio State
Holiday Bowl - #7 Oregon vs. #6 Boise State
Orange Bowl - TBD (Georgia Tech, if they won the Chick-fil-A Bowl) vs. TBD
Sugar Bowl - #1 Alabama vs. TBD
Fiesta Bowl - #2 Texas vs. TBD
Rose Bowl - TBD (Oregon, if they won the Holiday Bowl) vs. TBD (Ohio State, if they won the Cotton Bowl)
*#3 Cincinnati and #4 TCU would receive the other byes, but wouldn't be assigned to a particular bowl.