HIO, I share some of your concerns. I'm just not as pessimistic as you. I acknowledge the issues you've pointed out, but also acknowledge a lot of the positives, the potential reasons for average or below-average performances (both at OSU and Nebraska), and the trends.
If your definition of average is based solely on overall record, then you are correct. His lifetime win percentage as a college head coach is 54.3%. But I can't base my definition simply on that. MR has clearly performed at an above average level when you look at the stats I posted above. Additionally, he has had some very respectable teams (four times finishing the season ranked in the AP poll - Guess what? Nebraska only finished the season ranked in the AP poll six times during that span), and he has coached and/or recruited 31 players selected in the NFL draft during that 2003-2014 period. This, in spite of the lower level of talent his teams have had.
I'm skeptical at times, but I also try to take a balanced look at everything, and what I see is positive. I think we have a really good coach who is moving the program in a positive direction.