How so? Manziel actually has very good accuracy and can make throws that some NFL quarterback's can't.
For starters, he's pretty small. You see RG3 already getting injured as a mobile QB, Manziel would get best up in the NFL.
He also gets to play in a very comfortable offense with two of the est offensive linemen in the country.
He's a good player no doubt. But there's guys that are great in college, and just average in the NFL. I think he's one of those guys.