I think a reasonable option would be to drop a team (Indiana would be a great fit in the Big East, a basketball conference) and then add two (I think Mizzou and Iowa State fit geographically and would add the Kansas City and St. Louis markets to the conference; Utah and BYU could join the Big 12). Another option would be to add Cincinnati (an up-and-coming football school that has been consistently solid in hoops) or Pittsburgh. Notre Dame would be weird because either tOSU, Michigan, and Notre Dame would have to be in the same division, or you would mess up traditional rivalries.