His game management decisions are elite. The only things I would consider clear mistakes would be attempting the field goal at Pittsburgh in the blizzard before the half and punting on 4th and 1 at around their 40 vs Cincy (the play before Wake ended the game with a walk off safety, just to show I'm not being results oriented).
He wins at 93% when he gets a good performance from his QB (passer rating 88+) which is good for second in the league only to Jim Harbaugh.
He deserves a third year because with a god awful GM it apparently takes more than 2 years to overhaul the entire team to fit his philosophy, which is the opposite of what Tony Sparano (and Rex Ryan) ran who relied on running the ball and stopping the run. I believe Philbin's philosophy is predicated on winning the passer rating differential -- if our QB outplays their QB we'll win. The philosophy may be too progressive for the NFL at this time, especially if Tannehill doesn't step up, but I want to see it through. If Tannehill becomes elite I could see us winning games by 40-50 points with this philosophy, which is a far cry from Wanny-ball.
I noticed you have a problem with the lack of perceived creativity in his game planning, well Philbin is a system coach and you're going to be disappointed if you like a guy that designs illustrious formations to account for a specific player from a specific team. But then I believe Pete Carroll is a system coach too and he didn't do too badly for himself...