Full round robin play, every year, in that scenario. Although it will never happen, my ideal would probably be 8 conferences of 9 or 10 teams each, with perhaps some "alliances" between conferences to play a de-facto conference championship/playoff 1st round between their champions. But the same thing could probably be achieved by having 4 "super" conferences of 18-20 teams, if you consider each division as basically a separate conference. Which isn't all that big of a stretch from what we have now, where VT only sees certain teams from the other division every 6 years or so. A lot of traditional rivalries might be lost in that scenario, though.