near-ish to each other. It mad the OOC games special because playing a Texas A&M or an Arizona was fun. It also make the post season more fun. You got match ups that you didn't see often (BYU vs Iowa State, Ohio State, Penn State, KSU....).
Also, with 10 teams you don't need a conference title game (although it is exciting to have).
Once you get to 12+ teams, you need two divisions (mini-conferences within the conference). Pods are dumb. Above 16 just gets forgettable.