The conference football slate will have to go to nine games. Which means you simply can't add two more powerhouse programs -- the league will have to add two programs that have a nice media footprint, above-average academics (hopefully) and, most importantly, will provided a relative lay-up each season for the other schools. FSU and Clemson? No chance. Think SMU, Tulane, Georgia Tech etc.
The football dollars will drive this, which is no surprise and which no one will complain about. The reason expansion will be necessary is because the committee deciding who gets in to the 4-team tournament will cast a negative eye towards an 8-game slate in the SEC (with four cupcake games, except for SC, UGA and UF), when most other conferences are playing 9-game conference schedules, i.e,; at least nine "real" games each season. The SEC will need to put appearances of doing the same, without turning the regular season into a death march for its member schools.