Sullivan's not the main problem. As noted above, the Pens have too many dollars allocated to too many old guys. I understand why they did it, I guess, but this team is going nowhere until they get some retirements and they rebuild. Scotty Bowman, Mike Babcock, and the ghost of Toe Blake together isn't enough to help this team.
Sullivan will ultimately take the fall, because that is the easiest thing to do, but none of this past season, nor the terror that likely will come next season, is his fault.