I think the Big 12 would be really stupid to jump from 12 schools to 16 schools by adding 4 PAC schools.
The PAC 12 was falling behind in revenue, in part because they were a west coast conference and there weren't enough eyeballs watching.
Then 2 of the more valuable teams leave, and it's the PAC 10. Still a west coast conference with not enough eyeballs watching.
If the Big 12 is paying attention, they would realize that strictly expanding west is not the best option.
3 PAC schools + UConn makes a lot more sense than 4 PAC schools.