I'm totally undecided on McCarthy. There are some who think he's an average HC who benefited from having a superior QB. There are others who think he's a very good HC. His teams were 125-77-2 during his Green Bay tenure. Went 10-8 in the playoffs. Those are pretty impressive #'s and I think regardless of the talent he had and the QB, that's pretty good in a division that includs the Vikings, Bears, and Lions.
But Jerry Jones has had a hard time keeping his fingers out of the cake batter. I don't see McCarthy doing well with that. And while Jason Garrett gets all the blame, I think the Cowboys issues currently have a lot to do with players being overrated and the team overhyped.