Honorable Mention: seifert and switzer
I'd say Switzer by a country mile. Seifert won multiple Super Bowls with the 49ers and did so with two different QBs( Yeah I know both QBs are Hall of Famers). But it still takes a good coach not to frick something up. The 49ers were always in the mix before Seifert's second title.
Billick is suspect that is for sure but the Ravens had a pretty good ground game that year. Jamal Lewis was a boss running the ball and they had a Hall of Fame TE in Shannon Sharpe. The QB play was awful though and they really didn't have a big time playmaker at WR.