I'm going out on a limb and stating the #1 reason the Bills had any success in the early 90s was due to one man: Bill Polian. I'd never question Levy's experience or sincerity, but I think the Bills went to four Super Bowls in spite of Levy, not because of him. Between Polian's deals and Ted Marchibroda's offensive schemes, the Bills were great. I think Levy did just enough to keep the team focused for success. A great coach (Don Shula, Bill Parcells, i.e.,) would have done even better things with that group of players.
What's my point? I don't put Marv Levy on a pedestal like some fans. I think Levy, without the aid of Bill Polian, set this team back a few years with his second stint decision making. Buddy Nix might not be the next Polian, but he's certainly better than what we've had lately.