I'm on the Horton bandwagon but find it interesting that Darell Bevell is never mentioned. He resume is similar to Mike McCoy and he sure has turned Seattle around this year. He won at Minnesota and Green Bay too.
I don't disagree completely about Bevell, but McCoy has a resume full of coaching guys that significantly overachieved while he was their coach. Some could even argue that Peyton had even better numbers this year with him than he would have had without him. Not saying he wouldn't still have had good numbers without him, but quite likely not quite as good of numbers.
Bevell on the other hand was the QB coach for Brett Favre in his declining years with the Packers and while he was the OC with the Vikings they put up some pretty "Cardinal esque" passing numbers even though most of that time they had AD to take the pressure off the QBs.
I have liked what I have seen from the Seahawks offense this year, but time will tell how much of that is just how good Russell Wilson is.