so UM had a great season, but OSU has not? That doesn't make too much sense.
It does partly make sense.
OSU, for the last 5 years or so, is 2nd in the nation to only Alabama in recruiting. They should be steamrolling everyone in the B1G every season. Instead they just flat out don't show up to at least 1 game a year, where they don't just get beat by some inferior team, they get the doors blown off. This season, they were predicted to win the east, win the big 10, and go to the playoff. They damn near struggled in every game except the last one...
There are these things called expectations that are set, sometimes unrealistically, before the season starts. The "media/experts" all predicted OSU to roll. These same media/experts picked Michigan to struggle, said to go 7-5/8-4 and finish behind OSU, PSU, and MSU in the east.
Michigan, on the other hand, far exceeded those early expectations (note that I did not refer to UM fans' expectations. Most of us expected this. OK, not the OSU annihilation, but you know what I mean.) Michigan finished 10-2 and 7-1, in a virtual tie with OSU, before the tiebreaker.
In closing, it is possible for one team to have a really good season and another, while beating the first team and still doing well, not have a great season, because they didn't quite meet expectations.
Of course, OSU could still blow the doors off of Northwestern and make the playoff. They could, also, lose to Northwestern.