If he can give us 10-15 good carries and 35-50 yards per game then he's done more than enough to justify his scholarship.
But I agree with your main premise; there's nothing in his past history to suggest he is going to do more than that.
His rushing performance in the Belk Bowl against a Virginia team that had only 4 healthy DL doesn't inspire much confidence, although in fairness Virginia had a Top 20 defense and the SC offense stunk for the entire game.