I'd take that 2011 defense over the next two iterations. History will be too harsh on that D IMO. That team ran into team after team forced to play in cockroach mode for 4 quarters. This is why they got that ridiculous amount of turnovers and its also why they gave up that ridiculous amount of yards. As a scoring defense they were average.
We had the best scoring offense in the NFL this last year and they were nowhere near that 2011 offense. That was something special.
2012 the defense was average in all aspects then destroyed in the playoffs. In 2013 the defense reached an all time low for the 2nd half of the year.