Both McCoy and Skinner were redshirt freshmen, which is a big difference. I was talking about true freshmen transitioning straight from high school to college ball in one off-season.
Also, I'm not sure about Madkin. Did he redshirt, and what were his stats? I couldn't find his stats for 98, though I'm pretty sure you won with defense in 1998, sort of like a better version of your 2007 team.
Edited to add: Matt Stafford struggled as a true frosh. Peyton Manning did alright, but he didn't light it up. Tim Tebow was used as a running QB. Ryan Mallette sucked at Michigan. Jimmy Clausen sucked at Notre Dame. There are a lot of very good QBs who struggled to get their offense going as true frosh. It's rare, if ever, that a true freshman comes right out of high school and leads a successful offense as a true freshman.