Already gave up annual games against Michigan, Michigan State, Penn State, and Ohio State. Getting guarantees against a single, contiguous, geographically meaningful conference (including Iowa, Minnesota, and either ND or Michigan State), and having the opportunity to put the likes of Michigan, Michigan State (or ND), Penn State, and Ohio State on a permanent rotation (two of them every year), while still having room for three other OOC games against quality opponents seems like a win. I'm ok with giving up Indiana to get there.
Which is how I get to an 8-team conference realignment.
If what you really want is return to the old Big and Pac-10 and a way to for ND into a conference, I like that idea, too (except the ND thing), but I'm not sure it's any more realistic. :-)
For the playoff, you could even do a regional quarterfinal, where the West and the Pacific always play each other, the Midwest and the East, Texas and Appalachia, and South and Atlantic South (or some similar combination, with the intent to avoid making a Florida team fly to Seattle, or vice versa). Then do nationally based neutral site semis and final.
Of course, another way to approach this would be to trim the fat, English Premier League style. Go to 8-team conferences by taking out the worst two, and make those teams fight for the scraps. Finish in the bottom two in your conference and you're out, replaced by the top of Tier 2 (whether that's Western Michigan, Northern Illinois, North Dakota, Indiana...).