I think the thing you're missing, is that Pryor was running an offense built for Todd Boeckmen. Terrelle, was literally on campus 6 weeks, before he took over as QB. Running a pro-style offense, built on pocket-passing.
The offense should be improved significantly over last year, even with the loss of Beanie and Robo, now that an offense is being installed to best use Terrelle (thats the word from Spring practice anyways).
And I'm not worried at all about the defense reloading..it always does. That's been the exciting thing under Tressel.....who's next to step up? I'm thinking Brian Rolle, Andre Amos, Devon Torrence, and Austin Spitler pick-up where the seniors left off with little drop in overall team defense. Not saying those guys are as good as Malcolm, Freeman, or JL....but it's nice when a system is in place, and you can plug guys into the system that have experience in it.....unlike UM, where DC's are treated like yesterday's garbage.