Bill, for whatever reason your dislike for Darius clouds your view of him. Was he dominant? No! Bad? No! The teams has bigger problems than his play.
As for Marrone, I agree with you at one level, whether it's him or Hackett, the game situation awareness and management has been poor, very poor, at times. And I totally agree with you that this happened again at the end of the half. Even if you just run the clock out, or way down, and go in with a 10 point lead, while maybe conservative, it is on the road and 10 points is pretty good at the half.
As for overall, you cannot deny that he has had the team prepared and ready to play every week. And all that with a rash of injuries at key positions, and not the least being QB. Overall, I would say better than Chan, but with some serious lessons to learn about game management.