BYU needs tough games to build credibility. Utah has built in credibility with the PAC-12. Texas can get to the BCS title game by playing nobody just by winning the Big 12.

If BYU joined the Big 12, you'd want an easier OOC schedule. Utah State, Hawaii and Nevada would be a great schedule with the Big 12. Maybe play 1 tougher OOC game with another BCS conference school like Washington State.

Utah's bowl is based on playing the PAC-12. The other games are just appetizers. If they win the PAC-12, they go to the Rose Bowl, even if they play Denver Beauty College in September. Why risk a loss and a tough game when you don't need it?

BYU has been in the MWC too long and still has the mid-major mentality. It's even worse with Indy and the need to prove oneself with tough OOC wins, since all BYU games are OOC.