The likely scenario is the Big 12 poaching Arizona and ASU. Essentially, being a west coast conference kills the Pac12 because their ratings are in the toilet with 10 pm ET primetime games for their national tv broadcasts. Since Arizona is in the mountain time zone (2 hours behind the east coast) they can afford to play in the Central Time Zone with Big 12 schools. Yeah, they'll play a lot of 8pm ET/7pm CT/6pm MT games, but that's better than bad ratings playing at 8pm MT games.
Pac12 would then probably poach 2-4 from the Mountain West and completely devalue their conference (not that the Arizona schools add much, but still more than any current MW team). Probably combo of Fresno, Boise, Nevada, UNLV. Mountain West poaches WAC and so it goes out in the Wild Wild West.
Big 12 stabilizes itself (although WVU would take this opportunity to negotiate a move to the ACC, especially if ND committed full time) leaving an open Big 12 spot for potentially a Houston or even Cincy over UConn (or more if they want to go to 16). Pitt gets their old friend back, and they add a premier football program (along with ND of course) which the conference needs badly, but bball not good enough to upset he folks in Tobacco Road.
Long story short, we are stuck in the AAC unless the Big 10 takes us and probably Cincy (c'mon Warde, flex that muscle) since the other P5s are moving to 16 teams. SEC probably would stay at 14 since they wouldn't want more mouths to feed, unless it was Texas/OU (the two of which would never leave the Big 12 since they're the top dogs in the conference and have all political leverage).