As I know at least one other poster has mentioned (and I'm sure more), Nebraska in the Big XII as it was *might* have made more sense than being in the B1G. But, the landscape of conferences was going to change, and the B1G was no exception.
Texas and OU were looking to move before Nebraska left (they were ready to go the PAC10), which prompted them to look for a better fit. The Big XII was at one point on the brink of extinction, and still might be. Nebraska moved to a conference with more overall stability. From a conference standpoint alone, making the move was the right decision.
The bigger question is about whether it has hurt us in football. To a degree, yes. I think recruiting in the B1G is harder for Nebraska because we lost some of the pipelines to Texas. The competition is generally tougher in the B1G which makes getting to a bowl, even in a bad year tougher (no free wins against KU, ISU, etc.- granted many of the bad programs in the conference have improved since we left). Tougher competition shouldn't be viewed as a negative, though. A good football program would succeed even with the harder schedule.
Our biggest problems have not been tied to the conference change. The problems with Pelini were the same in both conferences- we could win the games we were supposed to win and would get laughed off the field in one to two games per year. Recruiting and player development went in the toilet under Riley. Frost came in and didn't realize how difficult the challenge at Nebraska would be.
The question ultimately comes down to would you rather be competing with schools like Ok State, TCU, BYU, Cincinnati *OR* Wisconsin, Iowa, Ohio State, Michigan, Penn State. Are either a perfect fit? No. But I believe one is very clearly the better fit.