The general tenor of fans from places like FSU and GT has been very lukewarm toward the Big 12 lately. It's easy to say, "Wow! Texas and Oklahoma!", but then people take a step back and remember this is a league where you also have to travel to Manhattan, Kansas and Ames, Iowa. This is NOT a "Sun Belt" league. The Big 12 is very much a paper tiger in this process - outside of its presence in the State of Texas itself, its demographics and footprint are by far the worst out of all of the power conferences. Pretty much everyone with a rudimentary understanding of conference realignment knows that the Big 12 would be a last resort for any ACC school. If the ACC is completely collapsing, then sure, you grab whatever life raft is available (even if it's in the Big 12). For the ACC schools that actually have legit options, though, all of them would pick either the SEC or Big Ten over the Big 12 without question. In fact, they'd all rather prefer that the ACC remain intact over the Big 12.
Bottom line: if you're actually hoping for an ACC school to choose the Big 12 *over* the Big Ten, there's NFW that it happens. The only ACC schools that the Big 12 could possibly get are the ones that the Big Ten and SEC don't want. Choosing between the SEC and Big Ten is a little bit of a different story, but remember that university presidents (as opposed to football-focused fans) are driving the decisions, and when the football *money* is going to be equal or better in the Big Ten *and* there's no contest on the academics front, I think it's wishful thinking that UNC would choose the SEC over the Big Ten, as well. Now, let me be clear, UNC's first choice by far is to stay in the ACC as-is, so in no means am I saying that UNC is actually moving to the Big Ten, but only that no one should think that they'd be choosing the SEC instead of the Big Ten in the event that they do decide that they need to move. Notwithstanding the fake grades and classes, the leadership at UNC is as academically snobby as anyone.