So you think someone with no coaching experience, at any level, is fit to be an NFL head coach? Right. Kelly, like Marino, isn't smart enough to be a quality head coach (I'm not saying Gailey is). I think you underestimate the level of depth needed to coach in the NFL, especially today, from the technical aspects (time management) to the philosophical (scheme) that Kelly simply doesn't have. Kelly has been out of the game for years; it would be far worse than Gibbs, a former Super Bowl head coach, coming back and being outmatched because of how the game had evolved.
Did you stop to think as to why Kelly might fail as a head coach, instead of "he led us to four Super Bowl appearances"? Your dream team of Kelly, Polian, and Bruce Smith would probably produce an 0-16 season, and that's not a slight at Polian, but rather this absurd concept.