I just have a gut feeling Young will be Tua and Sam Bradford rolled into one. It is not just his height, he has a slight build, that will be hard to keep weight on.
Yeah to me you can be short or slight, but both? That's cause for pause when you're drafting a guy #1 or #2 overall. Most of the short QBs I've seen have success were built pretty solid like Drew and Russ. Young is Doug Futie small.