Not saying he won't make it, just saying that's why he probably didn't get all that much attention from bigger schools. You know as well as I do that scouts tend to get caught up in the numbers and pretty much stop there. This guy probably has all the tools in the world, but the first thing a scout will tell his boss is that the kid's 5-10. That's just the way it is.
You want to talk about short QBs, you could also mention Joe Theismann, Billy Kilmer and Fran Tarkenton. All were listed as 6-0, but were probably closer to 5-10.