Rittenberg today made his grand entrance into the discussion, with a proposed divisional alignment that, in my opinion, is just way too complicated. I get that divisions need to maintain a competitive balance, and they need to maintain rivalries, and that geography is really the last thing on anyone's mind, even though it does enter the discussion. But I don't think you can just ignore geography completely.
OSU, Michigan, Penn State and Nebraska are generally accepted as the "traditional powers" when discussing division alignment, and you'll get no argument here. So let's consider that the top tier. Then let's lay out two more tiers...
Tier 1: OSU, Michigan, Penn State, Nebraska
Tier 2: Iowa, Wisconsin, Illinois, Michigan State
Tier 3: Minnesota, NWestern, Purdue, Indiana
We can all argue about how Northwestern is on the rise, and we can argue about how Illinois is down but are generally competitive, and that Purdue is on its way back, and we can bring all of the historical records we want to the table... fine. This is just one man's argument.
If the tiers listed above hold true, in a 12 team conference, we of course want 2 teams from each tier in each division. This, in theory, should take care of the issue of competitive balance.
To continue the formula that the Big Ten has mentioned, the next two most important factors, in order, are rivalries, followed by geography.
Now, I've seen only two arguments about this. The first is that an East-West divisional split makes sense because of geography, while still maintaining rivalries, and manages to do a reasonable job of maintaining competitive balance. The other argument is Rittenberg's, that the East-West split doesn't get competitive balance close enough, so let's completely ignore geography and only focus on balance and protecting rivalries.
What I haven't seen is anybody arguing for a different kind of geographic split besides the obvious East-West option, so I decided to look at the possibility of a North-South split that accounts for geography and hopefully also maintains rivalries and balance. In my mind it would look like this:
Tier 1 teams: Nebraska, Michigan
Tier 2: Wisconsin, Michigan State
Tier 3: Minnesota, NWestern
Tier 1 teams: OSU, PSU
Tier 2: Iowa, Illinois
Tier 3: Indiana, Purdue
Clearly each team would play their 5 other divisional opponents every year, followed by a combination of a protected rivalry (you've seen them all over the internet, I'm not going to rehash them here), and a round-robin of teams from the opposite division.
You are still going to have protected rivalries across divisional lines, which is a given, but in this scenario you have natural protection of some rivalries, and can still easily protect many others across divisional lines.
For example, Minnesota would play each of these teams EVERY year:
Iowa (protected rivalry)
From here there are options...
1) Two more conference games on a rotating schedule of the other 5 schools from the Big Ten South, and still schedule 4 non-conference games.
2) A second protected rivalry (Iowa would still want to play Wisconsin every year and you'd probably like to see Nebraska play Iowa and OSU/PSU, etc), bringing the list of conference teams you'd play every year to 7. This would then mean that the final conference game would be rotated among the remaining teams in the other division. The unfortunate thing would be that you'd only see those other teams once every 4 years (i.e. Minnesota would only see Ohio State every 4 years).
3) A second protected rivalry game and drop the number of non-conference game to 3 (like the Pac10 has been doing for years). In this scenario Minnesota would see Ohio State at least every two years.
There's going to be flaws with every system, and some of you have maybe already tuned me out (Jeffrick) because I have Ohio State and Michigan in separate divisions. Personally, I like the idea of having Michigan and Ohio State in separate divisions. Assuming Michigan regains its composure and joins the national power discussion in the coming years, I can't bring myself to envision a Big Ten where Michigan and Ohio State would NEVER play for the Big Ten title. I realize that by protecting rivalries and then having them in separate divisions that means they may play twice a year, and possibly on consecutive weeks, but again, I just can't envision those two never being able to play in the Big Ten title game, which would be the case if they were in the same division.
Personally, I would like to see geography come into play with these divisions. The Big Ten is already a regionally proud conference and I think there's merit in maintaining regional flavor when splitting divisions. I also realize how difficult that is, which is why I set out to look at another option.