Personally I don't think he did anything great to keep his job, but I don't really think he did anything to get fired. From a fan of another team it looks pretty cut and dry I'm sure, but it was understood that he had one of the more complex schemes in the NFL and while some of the starters had a rough time picking it up, they were signing players like Ernie Simms and Brady Poppinga off the street to play down the stretch. 2 DTs, 3 or 4 lbs, a starting safety all out...the guts off that defense were ripped to shreds and I think that had everything to do with the failures in the end. I couldn't even tell you who a few guys on the defensive end were at times. I would've like to see him stay another year and see what would happen. As I said though, I think Garrett and/or Jones wanted him out because of his belligerent antics and his big mouth.
They needed a new head coach.