Brad was a great assistant because he could provide the connection on a human level to the players. At the Pro plevel, Hac is dealing with "professionals" (for the most part). So they get it with his style. Brad could never be a pro coach, IMHO.
Hak was an excellent recruiter. I will give him that. He was also great at getting the team ready for the second half of the season. He just didn't have the ability to drive them to a championship.