It's risk-reward. Last year it cost the conference, this year it was a benefit.
After 2011, we (Bama fans) can't really argue that point too much with any real legitimacy. However, Ou and the Big 12 no doubt recall 2003 where KState nearly ruined it for the Big12 by upsetting OU in the CG, although the bcs computers allowed them to play in the CG. So, framed in that, playing a CCG with a round Robin may not seem worthwhile.
Personally, I think the risk isn't worth it. Just play the extra game and get the "One true champion." Reduces doubt and controversy.