Uhhh, where do I begin? Let's start with Gardner. He's, as you said, a serviceable QB with a lot of flaws in his throwing motion. Is he a step down from Denard? bsolutely. While he is a threat to tuck and run, he doesn't have the same type of electricity that makes defenses stack the box in order to stop him.
With regard to Fitz, he tore his ACL. He's a wildcard plain and simple. If he has a full and complete recovery, he will be a pretty solid RB. But remember this, even before he went down with the injury, his YPC was down 1.6 yards from 2011 to 2012. Is there potential at the RB position with Green and Bell? Absolutely. Is the talent also completely unproven? Bet your ass. Can't count on freshmen to be work horses. Same thing applies to the WR position. Gardner's fundamentals come into play on short routes that require timing. His three-quarters motion is ugly and slow. If you want to rely on the jump ball offense, be my guest. I'm glad you like your chances with freshmen receivers with MAC-level scholarship offers, because I sure as hell wouldn't.
Now there is real talent on the OL, and that will be a strength for years to come. But, c'mon man, they're not the ones with the ball in their hands. Also might want to temper your thoughts on Kalis right now, last I checked he was running with the 2nd team. Let me put it this way, I would not trade even one skill-position player on Michigan's team this year for one at Ohio State. Funchess? Maybe. But literally no one else.
I'm not telling myself anything either. I'm simply looking at a depleted offense with a lack of talent and speed, which I've heard is overrated by the way, and making a prediction. I'll stand by my prediction too. 8-4 in the regular season.