I just think the big 12 hype is a little overblown. they are essentially the teams nobody wanted from the old big 12, pac 12 and some aac teams that moved up.
the acc lost south carolina in 1971 and maryland.
the big 12 has lost nebraska, missouri, oklahoma, texas, texas a&m, colorado (once)
even if the acc loses it's top 4 to sec, they will be able to back fill quite easily and maybe even with some big 12 teams.
the power 2 don't want anyone else from big 12 so I guess they have that going for them.