Not sure I agree with the firing Tresey motif just yet. There's some evidence for, and some against.
Against Firing: Against NSDU, YSU frequently used five-man fronts as opposed to its customary use of four, and the D still couldn't get to the opposing QB. In other words, the coach changed the game plan in a sensible way, and the players couldn't execute. The quality of the recruit is partially a Tresey issue, but his best people would just be freshmen this year.
Also, I'm more willing to give Tresey a pass on the DBs than others. The zone defense has been creating some holes for easy passes, but it has also created some turnovers. Certainly part of the issue here is the defensive line: If there is no pressure on the QB, the receiver only needs a step to the DB to get burned. Pretty easy for a YSU DB to get burned.
For Firing: The linebackers are positioned too far back from the line. Normally they should fill the gaps. Against the YSU defense, an opposing RB has a couple of yards to pick up speed before hitting the LBs. Makes the tackling much harder. Looks like bad strategy from an alleged defensive genius.
Undecided: The tackling against NSDU was atrocious. Actually, it wasn't tackling--it was more like run into an opposing player and hoping he falls down. Not sure if it's the coaches not teaching how to tackle or the players not learning it. However, this mess is on Tresey's watch, and he is responsible for fixing it.