James Franklin is a terrible fit at coach for him. Blitz heavy defenses teed off on Penn State because they changed their starting offensive line basically every game, which led to having no continuity. Having no continuity means that he was basically running for his life on every play outside of a few games where they faced lesser front seven talent that matched PSUs equally shitty OL talent (San Diego State, for example).
To counter blitz-heavy defenses, Jon Donovan (the OC at the time who was later fired for being a stubborn idiot) generally had a philosophy with Hackenberg where he would keep six in to protect while taking shots deep down field in one on one coverage. That worked for the most part against the likes of SDSU and Maryland, but against a good front seven like Temple he just got fucking destroyed all day because they couldnt protect him long enough to make the DC pay for blitzing.
You see, theres two ways you can punish defenses for blitzing. You can either try to protect and go over the top for big plays, which usually results in DCs getting timid and switching from single high shells into two-deep shells, or you can go with the quick game and hit hots/underneath passes to just go with a death-by-thousand-papercuts game plan. Donovan heavily favored the deep ball to try to get a big play against the blitz, but he simply refused to acknowledge that he never had a good enough offensive line to execute that game plan on a weekly basis. In essence
he Mike Martzd the Penn State offense. When it works, it WORKS (i.e. Penn State vs Maryland)
but you need the right line for it and the right opponent.
Conversely, Bill OBriens philosophy for beating the blitz is more flexible. In New England and in Hacks freshman year, he generally advocated for countering the blitz with hot routes, quick throws, and occasionally taking a deep shot or working in a pump-and-go if he got the right look for it and his QB was in rhythm. OBrien was never arrogant enough to think that downfield throws all day would work when the offensive line couldnt hold up, so naturally Hack had more success against the blitz in his freshman year. Philosophically, OBrien had a better understanding of how to work with his personnel and his quarterback than Franklin and Donovan did.
Secondly, Hack is not a primarily pistol/shotgun spread quarterback. His accuracy problems were 80-85% the fault of terrible footwork, and based on my charting nearly all of that shitty footwork was in the pistol or the gun. When working under center on pro-style concepts under Franklin/Donovan, Hacks footwork was more or less impeccable, and as a result his accuracy skyrocketed. In particular, throwing on the run on boots/half-rolls was a huge strength of his on play action. Its almost like he grew up as an under center QB and never really did anything from the shotgun in his youth, so he never "learned" how to be a shotgun QB. Its the exact opposite problem that spread prospects like Mariota had considering they had to "learn" pro-style footwork from under center. That was a new world for him under Franklin. Its almost like when he wasnt moving his feet during a pro-style 3-5-7 step drop, he completely forgot to move them at all, and thats where the accuracy mess came from.
It took me about a month of film study to notice that pattern in him, but once I went back and looked at all my logs it made complete sense, and from then on all of his tape had a whole new context. This is a big, strong-armed QB with excellent leadership skills, toughness, football IQ, and work ethic. I dont remember the last time one of those prospects lasted until the second round just because he had a shitty head coach who refused to accommodate his skillset."