Expanded AAC:
K-State, Baylor, TCU, SMU, Houston, Tulsa, Tulane
UCF, USF, ECU, Navy, Temple, Cincinnati, Memphis

Reorganized B12:
K-State, Houston, Memphis, Cincinnati, UCF, USF
Baylor, TCU, BYU, Boise State, SDSU, UNLV

You can build a "best of the rest" conference from the remains of the B12 using the Big-12 brand, which likely means more TV money. You can't do that with the AAC. You're stuck with the likes of Tulsa no matter what. In the B12 you get to 12 teams and then see who rises to the top over the next few years among the rest of the G5s and then you can add whoever you want among Colorado State, Fresno State, SMU, East Carolina, Temple, Tulane, etc.