The rookie contracts aren't what they used to be. Additionally as quarterback you need to be able to pass the NFL...as in, can you play in the NFL. While he is dynamic and no doubt a terrific player he has much to work on to be viable at the next level. (See Tim Tebow)
Who cares about Tebow. Many had him pegged for NFL failure before he was ever drafted. You wanna talk apples to apples, I'd compare his running and passing abilities to guys like Vick and RG3...