I would hate two eight team divisions - that's like having two conferences whose champions play each other. If we expand further I maintain the best approach to football is to have no divisions and have the schools do their own scheduling of nine conference games per year. With sixteen schools you would play nine and miss playing six each year. Natural rivalries would develop. Traditional playing dates would emerge as they did in the old SEC when they used this approach when we were in the conference. The ninth game would give plenty of conference game volume for TV. Have a championship between the two schools with the best conference record. Break ties first with head to head results and next with their Playoff Ranking which allows strength of schedule to factor in. Very simple and effective.
I believe I would even use the same basic format for other sports. If you want 20 conference games in basketball, schedule your own ten home and home series. Seed the tournament 1 through 16 based on conference record, with ties broken by head to head first and RPI second.