ASU and Utah joining UA/CU in going to the Big 12 makes the most sense, and UW/Oregon going to Big 10 would then make sense even though it will piss of USC to essentially eliminate the Pac 12, create a Power 4, and I think it would make sense to have the 4 conference champions get auto-bids and then the highest rated FBS non-Power 4 to get an auto-bid with 3 "wild cards" in the 8 team football playoff.
The rest of the Pac gets left out in the cold. I know it isn't logistical given the $ involved for a smaller conference, and would be a big step down for them, but Stanford and (to a slightly lesser degree) Cal joining the Ivy League would be really cool and make sense given their academic prestige.