His throwing mechanics are fine, I think. Not sure if you meant that specifically or overall mechanics. His footwork on his drops could use a little cleanup, but I think that's a result of putting him in a shotgun/spread offense when he really ought to be in a more pro-style offense.I think he has the potential to be a high draft pick because of his size, arm strength, and mobility... however his mechanics are terrible. His progression and pre snap reads need work. Also he has terrible footwork after his initial read and gets what many call happy feet. There were double digits where he began to scramble at times he should have stood in the pocket and delivered the ball (although there was great coverage) he bailed out way to early and way to often. He has alot of work to do in taking his drops if he wants to succeed at this and the next level.
His biggest problem (as you pointed out) is happy feet. He made the O-line look a LOT worse than they really were. NU certainly got pressure at times, but even when they didn't, he ran into it unnecessarily. This has been a problem for 2 years, now.