Ah, I see... You just haven't watched him enough.
All I know is that McFadden ran away and left everyone on LSU's team, including Mr. 4.37 Laron Landry. He's got tons of speed. If he ran a 10.8 100m, it was uphill, into the wind, on a cinder track.
I think part of McFadden's "problem" is that he makes the game look too easy. That's one of the worst cliches in sports, but it's true. You don't do what he's done with mediocre speed, or by making only one cut. He makes guys miss, he just does it subtly, without wasted motion. He reminds me a little of Marcus Allen in that way.
I don't like to hype college guys too much because so many of them are compared to all-time greats before they've done a thing. But McFadden is the best I've seen in a long time. From what I've seen up to this point, he'll easily be better than Peterson.