Yes, the attacks on PP go beyond rational criticism to angry hysteria. His recruiting has been solid, given the situation he landed in. Great? No. Looking at the players leaving for the NFL suggests to me that he knows how to coach a team in practice and that players improve under him. By the way, I think this was Calhoun's strength as well and I never felt he was more than just "good" as a game coach.
Everyone screams about the poor in game performances, especially last year. But as Belichick always says, the coaches don't run the ball, throw the ball, catch the ball, tackle or block. At some point it is on them. Looking back on the season I see a team with a very good defense. So good that if they can run the ball, control it, and score even a little, and not turn it over, they win. So GDL crashes an undersized RB into the line, and when we can't run, Whitmer airs it out, and the turnovers fall like rain. Was the strategy great? No, but I do think our personnel on offense last year were a horrible match to our strong D. We needed an accurate short passer, and bruising ball carrier to complement that D. We had an inaccurate QB, who turned it over way too much and forced the ball, and a small RB that couldn't make yards after contact. The inability of the coaches to adapt to that personnel, and find a way to run a ball control offense despite them, was their biggest failure.
In 2013 I don't think you will see a wide open passing offense. I expect the passing offense to use quicker reads and shorter routes, a more a West Coast style offense. More screens and passing to the backs. Cutting down the turnovers has to be a huge priority.