Blame Hackett for the poor play calling in the second half.
Marrone had clock management issues for sure, but he may have allowed Hackett to call the O plays. Marrone's fault, as it was when with the Bills, was his liking and allegiance to Hackett. Unfortunately, he did not learn his lesson and took him to Jacksonville as well. I wont be surprised if Coughlin puts his foot down and orders Marrone to fire Hackett.
However, Marrone certainly did pretty good for the overall season.