Certainly losing OU and UT to the SEC hurts the Big 12, but from a strength standpoint, adding Cincy and BYU, Houston, and UCF are all solid and 3 of those 4 are in the top 25. No blue blooods in the Big 12 is still concerning, but I think the league still looks at least as good as the Pac 12.
But the Pac 12 is in trouble. They do have the blue blood programs in USC, Washington, and the upstart blue blood Oregon, but there is a big problem with the shifting demographics and culture in the west. I was talking to a collegue of mine who graduated from SC and who has direct ties to the football program this morning, and he agrees. USC is unique and with the right coach I think they will come to dominate the Pac 12 again, but for many of the programs in the Pac 12, they have a big problem on their hand. The type of students that are going to schools like UCLA, Cal, Stanford, Washington, OSU, and the growing apathy towards sports may be mortally wounding the Pac 12.
Schools like Utah, the AZ schools and USC do not have the same culture that the rest of the schools in the Pac 12 have.
As I think about things, I don't know that any of the schools left in the Big 12 are attractive enough to be ppached from the Big 12, as none are blue blood, long time traditional powers in CFB. But the Pac 12 does have several programs that are still considered blue bloods. Could USC and a few other schools say goodbye to the Pac 12 and leave for another conference in the coming years?