The question should not be about which school is closer geographically, but which schools stabilize the conference for the long-term. If I'm Texas Tech, Baylor, IA St., Kansas State who are in danger of being left behind I want UConn, Cincy, BYU, UCF before I want Houston, Memphis, Boise, Conf USA III et al. IF however, Texas, OK, KS have no intention of staying in the Big12 then the question is moot. So we should be building a consensus with those schools who are worried about being left behind to force the issue, as well as working relationships with the bigger schools who could potentially include us in a move to B1G.
I actually think you are close to reality here in terms of Oklahoma's sabre rattling. If Texas was gone, they would then assume the de facto lead of the conference. Adios Texas. They may very well be representing all of the existing b12 teams at this point, and would be willing to part ways with them to keep the rest of their core group together.