Until the B1G signs a non-at-the-time AAU school, they are a conference that doesn't sign non-AAU schools like Florida St. While I suppose that Florida St could join the Big 12 or something, the SEC makes a ton of sense regardless of what Florida thinks because conferences are always growing or dying. That's my opinion on Florida St until something happens with that school changes it.
Speaking of AAU, if Miami was available that's a school that the B1G would look at.