I think people either don't know WHAT prestige means, or they forgot. Prestige is your reputation.
I'm pretty sure the OC with a high prestige rating would affect JUST the offense. Same for the DC. But coaches don't directly affect how player play in real life anyway. If that was the case, you'd think we wouldn't have guys like Tate Forcier being touted as a bust right now, right?
Prestige is basically a respect rating. Ohio State has a 6-star because they are a respected, dominant powerhouse in the NCAA. Jim Tressel probably has an A+ because when guys come to Ohio St. they will listen, pay attention, and learn.
Think about it like this: You think Phil Jackson made Kobe Bryant play better? Or is Kobe just THAT good? Look at LeBron. Mike Brown made him a better defender while he was with Cleveland. So now that he's in Miami with a different coach, he's just supposed to magically not know how to play defense as well because he plays for a less-experienced coach?
The only thing coaches do is make players better. The players
PLAY, the coaches
COACH. Hence, the reason why coaches affect progression. Just because a coach is an offensive-minded coach doesn't mean guys will automatically run better routes and catch better. The guys have to know HOW, right?
BTW, I'm not some guy who THINKS he knows about football. I've been playing all my life, and I plan ot at least try to walk-on in college, hopefully my sophomore year.