I can't follow your logic. If the Big XII only expanded by 2, without FSU, then who are they adding? Louisville? USF? Rutgers? How does that make that league a powerhouse that it isn't already, one that locks FSU out of some big boys club? So you're suggesting that they jump to the Big XII because they might miss the train, but the train is waiting on *them*. Not one school that has switched conferences in the past couple years has done it other than as being a clear upgrade to where they were previously. FSU might jump but they aren't doing it out of fear.
As to #4, how would that ACC home schedule be any different than if they were playing Texas, Baylor, Iowa State and Kansas State. One marquee team (like when they play Clemson or Miami or VaTech) and a whole lot of "meh". They're going to jump leagues to sell 5K more tickets every other year? Again, they may jump, but that's not why.
*edit* FWIW, FSU has always had attendance issues. Even in their heyday Bowden would complain that they didn't sell out for the scrubs on their schedule. Doak Campbell is a HUGE stadium, probably 10K seats too big relative to the size of their fanbase. Just a quick search shows that in 1999, the year FSU won a national title, they averaged 78,725 per game, which is almost 2K short of capacity. FSU is not UF.
*edit 2* Last year FSU averaged 77,842, and that's without playing UF at home. So that ACC schedule isn't exactly killing them.