If you want to understand him, think Jordan Eberle.
Good junior numbers, a ton of people thinking he can't produce at the NHL level, and national hero after scoring some clutch goals.
Tebow is pretty much the same. Dominant college career, a lot of scouts knocking his throwing arm as a QB, and just heroic in the fourth quarter of a game. He's built up a reputation for essentially doing nothing the whole game, but then when it comes down to the closing of a game... he wins it.