He's never sniffed a national title, even though he's been in one title game. He's had too many 8 win stinkers and a true hellish 4 win season. He's had 21 games vacated by the NCAA. He's never won a major bowl, with wins in the Sun, Pinstripe, Music City, Citrus, and Camping World.
His ceiling is very good, as we've seen of late. That being said, his ceiling is not good enough to win a title, nor compete with the current elite programs. He's erased the futility of the Davie-Willingham-Weis era's, and has hopefully set the table for the next coach to reach the promised land.