Culture is the biggest thing. I think we had common culture with everyone from Oklahoma north, but once the Texas schools showed up, the culture changed dramatically, and we no longer fit. Colorado never really fit, either - they're far more a West Coast school than a Midwest school. They'll prosper in the Pac-12.
We'll prosper in the Big Ten, if for no other reason than the fact that we're so very much like Illinois, Iowa, Minnesota, Wisconsin, Indiana, Michigan, Sparty, Ohio State, etc. We're unlike PSU and Northwestern, but not so tribly much so that we can't find common ground. It seemed like, no matter what happened, we just could not get on the same page as Texas, Texas Tech or Baylor. A&M was somewhat like us, but not tremendously so, either.
Not sure the Big 10 will be different in football then the Big X!! was, but basketball will only bring your program up a step or two, as well as "most" other sports programs with the exception of baseball. NU will bring Big Ten baseball up a notch or 3! In Academics, you will rise very high, as now NU will receive BILLIONS in CCC reasearch money, being a member of the BIG *hate that logo). In football you will finf natural "Big Time" rivals in U of M , Penn ST, tOSU and Iowa. You will find warm rivals in MSU, Wisky, and maybe Illinois. You will worry about having an off day against Northwestern, Minny, and Purdue. You will never worry about Indiana till Basketball. To start a rival in the Big 10, you have done that already, No one in the Old Big 10 wants a new member to winn the conference. Best of Luck Nebraska Red!