Interesting question, with many things to consider. Without getting into PFF ranks, here's some basic stats to look at before answering.
In 2011, we scored an average of 20.6 points per game, and gave up an average of 19.6.
In 2012, we scored an average of 18.7 points per game, and gave up an average of 20.5.
Not much of any difference so far but, with tuff games ahead, the nod goes to 2011.
In 2011, we passed for 214 yds, 12.2 avg, and 20 TD's, ran for 124, 4.2 avg, and 11 TD's.
In 2012, we passed for 225 yds, 11.8 avg, and 7 TD's, ran for 100, 3.6 avg, and 11 TD's.
Looks like an overall toss up here, with 2011 getting an edge, so far.
In 2011, we gave up 282 yds passing, 11.8 avg, and 12 TD's, 95 yards, 3.7 avg, and 7 TD's run.
In 2012, we gave up 264 yds passing, 12.2 avg, and 12 TD's, 97 yards, 3.8 avg, and 4 TD's run.
Passing TD's given up gives the edge to 2011, so far.
As I said, there are many things to consider, other than just the above stats. Rookie QB&HC, scheme, lockout, etc.