I am sure that everyone in the Big 12 is wary of what Texas may do in the future. BUT, Texas football is in a great position within the Big 12 to dominate and easily make the college football playoffs. Think about it. The only real traditional football power in the Big 12 outside of Texas is Oklahoma. (Yes, the OSUs, WVUs, KSU's can have good seasons, but they can't be dominant in the Big 12. over the long haul.) It's like the ACC with Florida St the only traditional power which means FSU should have an easy path to the playoffs most years.
Realistically, I think the most likely landing spot for Texas is the Pac 12. Think about it:
Pac East: Texas, Texas Tech, Oklahoma, Oklahoma St., Colorado, Utah, Arizona, Arizona St.
Pac West: USC, UCLA, Stanford, Cal, Oregon, Oregon St., Washington, Washington St.