It really is just a matter of numbers from when the Big Ten had ten teams: six Big Ten teams in the West (IA, MN, WI, NW, IL, Purdue) to only four Big Ten teams in the East (IN, MI, MSU, OSU). I also think Nebraska as an institution and a people fit in better with the western schools, particularly IA, MN and WI. I guess this is like a lot of occasions on this board when I am looking at a lot of non-football factors and the Nebraska folks on here just kind of focus on football as the end all, be all.
Only non-football factor is Hockey....
In the b1g, Minnesota rules and Neb drools