Bill Polian's Manziel concerns...
1. He's not going to get appreciably taller,
2. His release point is 3/4s so he won't be releasing it like he's 6'1 1/2" or 6'2"... and defenses will play to that with mush rush and getting their hands up so you're going to have to create a firm front 3 (G-C-G), no inside rush.
3. He's a runner, he has magic outside of the pocket and that will translate into injury so you'd better plan for that because it'll happen