Part of the issue, in my opinion, is he made a mistake hiring Longo as OC. I was intrigued by the hire at first but you need a really good QB to make it work and the O LIne play is presumably much different than what they were used to. It was a very tough transition. Now you're on year 1 of a new guy at OC while you've recruited to the old guy's style of play for three years.
As for the defense....Tressel is maybe just kind of a meh coordinator.
Lastly, Fickell just seems like a boring, risk-averse in-game coach.