Tebow thinks he can still be an NFL quarterback, so he's going to try to play like one. I think it's possible that he ends up screwing himself out of a productive career as an option quarterback in the CFL in an effort to become something he's not.
It almost like changing positions. Some players do it out of desperation, and they lose, like, 30 pounds and completely change their bodies. If they don't make it at that new position, they've pretty much screwed themselves over, because they no longer have the body type to play their old position.
That's what was hurting Paul Kruger his first couple of years. The Ravens wanted him to bulk up to play the 5-technique. He wasn't good at it, but he was too heavy to go back to the SLB. It took him another year to lose the weight and get back to form. He was a second-rounder. For guys who are on the fringe of being cut, they often don't get that year to switch back.
If Tebow tries to be a pocket-passer for a year in the CFL and fails, then he might not even get a chance to play as an option quarterback. That's the concern that I would have if I were he.