Playing in a brutally tough SEC has made Dooley look worse than he is, and playing in a largely-pathetic Big 10 made Tressel look better than he was.
Yes, Tressel won at Youngstown State. To be diplomatic, it wasn't a clean win, since we all know exactly how he was able to keep certain players on the field who the NCAA would later take quite an interest in. Wins against rivals are overrated, but are absolutely holy to OSU fans. The title game against Miami involved a Hurricanes team substantially worse than the year prior, loaded with young players who weren't close to reaching their potential (and thanks to Larry Coker, never would in college).
You know who has won at every level with nary a scandal or an NCAA investigation following him? Paul Johnson. When he was OC at Hawaii, he was with a Warriors squad that had only touched 300 points in a season twice in school history; they scored 300+ points every year that he was there, including two years of over 400. At Navy, he guided the most prolific offenses in school history despite clearly deficient talent, and he brought an ACC title to Georgia Tech. His Navy teams beat Army every year, and Air Force every year but one. 14-3 in D-1AA playoff games. And he's clearly won with teams that suffer in the talent department, which Tressel knows nothing about.