I wouldn't leave FSU for LSU. Heck I wouldn't leave FSU for any place, except Tennessee of course. FSU has been one of the most winningest programs the last 40 years. Bowden built a powerhouse and Fisher has inherited it and done a great job as well. He has become the face of that program, it's been his home for years, his kids are in school there, the facilities are just as nice as LSU, if not better, and I know money won't be an issue.
However, as a coach he may strive to accept new challenges and winning in the SEC is a different breed than winning in the ACC. The competition is not the same week in week out. But why would you want to come compete with Saban? Lol