I would say look at a guy like Billick. Cutting edge offense for the time. Yet he was enough of a leader to turn a perennial loser franchise that couldn't beat the Jags to world champs against all odds with a pedestrian offense at best.
Harbaugh has has a special teams background but his great leadership is what brought a young offense and diminishing defense to perennial contenders and champions.
Belichicks defenses have been less than stellar in their last three super bowl appearances.