Oh, what a bigger difference a half-dozen injuries can make. In 2011, with a little help from the opposite sideline, Missouri beat Texas A&M. In 2012, A&M literally could have called students from the stands to play the second half and still won. That has nothing to do with playing in the SEC. Pinkel got .045 points per pass from his quarterbacks in 2012, half as many as Rutgers.
The defense was underrated, top 20 by most metrics. It allowed 1.9 points per possession, but 142 of those points came against Georgia, Alabama and Texas A&M, three of the nation's four most efficient offenses. Performances against Tennessee, Syracuse and Texas A&M to close out the season were uninspired, but Missouri's D was quite good through the rest of the season when playing against mortals. They could have been much better if they hadn't allowed more than 5 points per possession in the red zone.