The Big Ten's 12 members are set in stone...at least for now, but the schedule is far from the same.
Right now, from all that I have read, there would either be a North/South division split, with the North getting Wisconsin, Minnesota, Iowa, Michigan, Michigan State, and either Ohio State or Penn State. The other, and from what I've read, more likely scenario, would be the East/West split depicted above. This is what I believe will occur. If you look at it, it's really a no-brainer.
The conference is currently set up so each team plays nine of the other 10 teams in any given year, with the remaining being rotated out of the schedule for two years at a time. Each team being "paired" with another two which are never rotated out is done to keep rivalries intact. The pairings are these (Retrieved from Wikipedia):
Illinois : Indiana, Northwestern
Indiana : Illinois, Purdue
Iowa : Minnesota, Wisconsin
Michigan : Michigan State, Ohio State
Michigan State : Michigan, Penn State
Minnesota : Iowa, Wisconsin
Northwestern : Illinois , Purdue
Ohio State : Michigan, Penn State
Penn State : Michigan State, Ohio State
Purdue : Indiana , Northwestern
Wisconsin : Iowa, Minnesota
Italics indicate a team pairing that would be unaffected by the East-West division alignment. So, as you can see, the major Big Ten rivalries would be left unaffected for the most part.
As for the rest of scheduling, I would recommend having each team in an inter-division round-robin (obviously), while also playing at least three teams from the other division.
Perhaps you could just switch out teams in the dual pairing system so both paired teams would, in the end, be inter-division rivals. Such a system, I believe would look something like this:
Illinois : Indiana, Purdue (Purdue Cannon)
Indiana : Illinois, Northwestern
Iowa : Penn State, Purdue
Michigan : Wisconsin, Minnesota (Little Brown Jug)
Michigan State : Indiana, Nebraska
Minnesota : Michigan, Penn State (Governor's Victory Bell)
Nebraska: Michigan State, Ohio State
Northwestern : Indiana, Penn State
Ohio State : Wisconsin, Nebraska
Penn State : Minnesota, Iowa
Purdue : Illinois, Northwestern
Wisconsin : Michigan, Ohio State
As you can see, combining the two systems could provide for some pretty awesome results.
Most of the inter-divisional rivalries remain intact (with the larger ones noted above). And look at some of the other marque matchups from the Big Ten. Yearly contests of Nebraska-Ohio State, or Wisconsin-Michigan. With this system, some of these rivalries will even be able to keep from taking those long two years off, like the Governor's Victory Bell for instance.
If there's one thing that will be a constant in a divisional Big Ten, it will be dramatic primetime games and rivalries.
Speaking of rivalries, how about some new ones involving the newest Big Ten goods? I'm sure Wisconsin is itching to show Nebraska who's really the Big Red. You can bet too that Ohio State won't want to give up its spot as one of the top two prestigious Big Ten programs (sorry Penn State, but you can't compare to OSU and Michigan).
The Big Ten really has the advantage over just about every conference rivalry-wise. And those big games will sure look to provide the Big Ten with a couple more primetime matchups to air on ABC. This new Big Ten will be a different one, but I for one believe it will be a change for the better.