With CCG deregulation, there is no constraint on "division" structure; by eliminating divisions, the implementation of "fair" and "balanced" schedules becomes much easier.
With 15 teams: Each team plays 2 annual rivals every year (hence the "annual rival" designation). In odd-years, teams play "Half A" (one group of 6 of the 12 remaining teams). In even-years, teams play "Half B" (other group of 6 of the remaining 12 teams). (Yes, for each team the composition of "annual rivals", "Half A", and "Half B" is unique, and it is *not* tied to "divisions" or "pods".)
An even number of conference games is inherently more "fair" than an odd number of conference games. (Equal quantity of home and away conference games)
-- If the B1G goes to ten conference games (to reach an even number), that leaves *2* games for OOC. Keep in mind there are presently 125 in FBS and 65 in P5. So the B1G could conceivably intermingle with the rest of the country twice a year????
With the method I described above, *everybody* plays *everybody* over the course of two years. Therefore, Iowa and Wisconsin end up playing Ohio State and Michigan more frequently in that structure than in the present structure even if not "annual rivals". (With two divisions, this *requires* the ten-game schedule [not 9] to ensure that with 14 teams, and a ten-game schedule is insufficient to ensure that with 16 teams.)
The issues at hand are not limited to Iowa and Wisconsin losing games with Ohio State and Michigan. Now Ohio State and Michigan are forced to play Maryland and Rutgers every year. Many Buckeyes are not enamored of this, either. Presuming Maryland and/or Rutgers are not designated as "annual rivals" for Ohio State and/or Michigan, the 15-team league with 8 conference games featuring 2 annual rivals resolves all of these issues. ("15" also addresses issues about "expansion partners" and the limited pool of "desirable candidates" for expansion).
The only problem I can think of with a 15-team league is that you never have the whole conference playing one another at a given time on the schedule. And that is just not that big a deal: Don't forget that ACC had 9 for awhile, B1G had 11 for awhile, ACC basketball now has 15, Big East basketball used to have 17.