I never did hate Callahan, thought he was a helluva offensive mind, but he wouldn't "at least" move Cosgrove to just a position coach and bring in a good DC, Callahan may have been able to stick around.
I didn't like his approach to Tom's legacy, the removal of the pictures of many of the great players who helped build this program, and i especially didn't like his treatment of the walkons. The dude never understood that the QB's best friend might have been that 4th team defensive tackle who was being treated like a non-person. Sent the message that if you weren't productive for me, you would/could become a non-person too.