It all depends on how he does. It also depends on the fact whether he's the type of QB that NFL teams are looking for. I'm sorry to say that i have no idea how strong his arm is (didn't see him throw the ball much last year), but if it is weak then NFL teams might not want him, or if they do draft him they could try to change his position. But, as i said it all depends on whether he is successful. No one has seen enough of him as a full-time starting QB to tell whether he will be a good starting QB.
I think he will be good college, especially in the urban meyer option type offense which he will be able to run even better with Tebow at the helm. BUT, this is not a system that most NFL teams use. This could deter teams from drafting him. As i said, he will be good in college, but i don't know about the NFL.
After saying all of this, i believe he will stay for his senior.