The BCS has been a debated topic, very heated. I see this in a realistic vision unlike most I've ever talked to.
Pros of a playoff:
It racks in the revenue for the NCAA, from sponsors giving extreme amounts of money to get their name on the bowls. These big money corporations will give extreme amounts of money for the games in the playoff. More games=more money.
More teams get more of a chance to win the national championship. This can also be a con too.
Cons of a playoff:
People are begging for a playoff system in order to find a true national champion. What if in a 12 team playoff, TCU upsets Florida. In a complete fluke happening, the universe shifts just for this game and Ole Miss beats Oklahoma. But Florida or Oklahoma might have gone undefeated in the two hardest conferences in the game. TCU and Ole Miss have no right to say they are more of the national champion then 12-0 SEC or Big 12 Champion.
You can't expect college kids to play more games then most NFL players! It's ludicrus.
Pros of the BCS:
You can center your entire day around one game, for one week. It is a joy. With more games, that means games would have to be on the same day, maybe even the same time.
It creates a buzz on who should be the actual National Championship throughout the offseason. This gets people talking about things other than recruiting.
Cons of the BCS:
Apparently it's illegal?