From the outside, looking in, There is nothing stucturally wrong with your base D. It isn't just always 3 on the front or 3 backers. The Griz D shows multiple looks and has motion to confuse blocking assignments. It is not easy for an offense to prepare for what UM throws at them.
Our QB was looking for potential 1 on 1 matchups with your secondary. Fortunately, he found them often and our receivers did well to beat their man. We seemed to catch you guys in safety blitzes often. It may have been a little play action as well.
At any rate, we didn't exactly stop your offense either. I feel like both of our Ds will stiffen up as the season progresses. At least, that is what I'm hoping.