Come on man. How can you not be surprised with how A&M has performed in the SEC? They had been a middling Big 12 program for at least a decade, and no one knew that Manziel would be this good. I thought they would be fighting for a bowl game. As for Mizzou versus A&M, Mizzou had been a much better program recently than A&M. Franklin was coming off a good year, but he was injured all season. I definitely thought Missouri would have a better season than A&M, and I think almost everyone thought that.
My points aren't an indictment on the SEC either. Sometimes a program gets tremendously lucky with a QB, and that can reverse fortunes. Look at Cam Newton at Auburn as an example. They were a decent team the year before, but a lucky QB addition changed everything.
I think that's the point. No one expected A&M to do what they did, but that doesn't mean the SEC is "overrated".