I think some of the reasoning was the fact that we were coming over a terrible offensive minded coach in T-Dog. Bears wanted to change up the mentality and get back to "Monsters of the Midway" so they went with an experienced Defensive coach over hiring Gase who was a young offensive coach.
Once again, this just points out how utterly incompetent the McCaskey's and Phillips are as personnel people
Look, hiring Gase as the head coach was fine in hindsight but in no way likely. He really didn't distinguish himself as OC in his one year with the Bears other than controlling Cutler. The big problem was the decision about hiring Fox. I said it at the time because the fit with Pace just didn't make sense to me from the beginning.
What the McCaskeys should do is to hire Tom Coughlin as their President of football operations and have him evaluate Pace and if he passes muster, they should hire a new head coach. With a real football guy in charge, they would have a chance to get back to respectability because of their likely draft position and salary cap situation.