Beyond the most obvious reason -- "settle it on the field" -- there are a lot of positives to instituting a playoff system. I'm going to offer a few of my reasons; feel free to comment or add yours.
- A truer test for the championship teams. Let's face it -- 5 weeks to game plan for a BCS bowl game or championship game is too much time. It shifts the balance of power from the players on the field to the coaches' "war rooms." It's too much time to design an entire battery of new plays and schemes specifically tailored to the team they're facing. If you've got a playoff system, with a week between games and no idea who you'll be playing next, it rewards the teams with the most solid fundamentals, since those are the teams best suited to adapt.
- Better NFL prep for the players. For those players who are looking to play on Sundays, let's give them some more "big game" experience. Let's give the fans and NFL scouts more to go on. Let's see how these guys perform in more "pressure situations." Ultimately, it could result in better football all weekend long.
- Back to tradition. The current BCS system has nothing to do with tradition. What's traditional about spreading the big bowls out across 4 different days, just so 4 of the 5 can be played in prime time? What's traditional about having to rush home from work to see the Championship Game? Play the first round of playoffs on New Year's Day in the traditional New Year's bowls. Seriously, who gets excited about watching 3rd- or 4th-place teams play in the Outback, Capital One, or Gator Bowl on New Year's Day? Let's have these New Year's bowls mean something again. If they wanted, the bowls could keep their traditional conference alliances; just make that part of the playoff system. Then play the semifinal round the weekend of the NFL divisional playoffs, and play the championship game on Saturday, the day before the NFL divisional championships... there you have it, "Football Championship Weekend." And the Super Bowl still has the privacy it deserves.
When every other NCAA sport has a playoff system, including the FCS and Div. 3 in football, the cries of "it's too much for the players" carry little water. D1 basketball's playoffs go on an entire month and involve far more travel for far more teams! We're talking about two additional weekends in an 8-team playoff, and only 4 teams' seasons are extended.
There are some changes I would make. I would do away with automatic bids for some of the conferences, since some of those teams have no right to be in the national championship hunt. What if conferences are judged by the out-of-conference schedules they play, in a formula that rewards each conference's OOC records and strength of schedule? The 4 strongest conferences get automatic bids; the remaining 4 slots are wild cards, but no second-place wild card could be taken over a conference champion with a better record. And how about forcing teams to play balanced home-and-away schedules, instead of some of these teams that play 8 home games and 4 away games? And if you want to be considered eligible for the FBS Championship, you must play an entire schedule of FBS teams. In other words, no powerhouses playing patsies to pad their win totals in hopes of making the playoffs.
In theory, the BCS was a step in the right direction, but it's been horribly flawed in its execution. The constant tweaks to the system are a testament to that. And frankly, I'm tired of having computers that have yet to watch a single football game determine who's best. You can say they're objective, but they're still programmed by people who are as biased in their ideas of what makes a team great as the poll voters. They just do their calculations with numbers and circuits instead of eyes and brains. And no set of data can truly identify greatness. So, to get back to the most obvious argument, let's settle it on the field. Bust the BCS for good.