Locker didn't play 4 years in a pro style offense either... he's only been playing in Sark's pro style system for 2 seasons.
I thought Mike Mayock made a great point about Locker's footwork, and it's the same reason a guy like Kaepernick is as raw as he is despite starting for 4 years at Nevada... they're both baseball prospects, who have dedicated a significant amount of time to the different techniques and footwork required to play certain positions in baseball.
Mayock made note of Jake Locker's footwork at the very top of his drop... his feet are too close together at the top of his drop, he lets his lead foot get too close to his back foot.
This causes him to have to overstride when he releases the football in order to compensate.... which leads to high, errant passes.
Jake Locker's hitch at the top of his drop right before he releases the football is the footwork ingrained in him from playing outfield in baseball... it's a curl-hop, which is what outfielders use when fielding a ball in the outfield to make a long throw back to bases in order to sting a runner. Locker only recently decided that he was going to dedicate 100% to football and leave baseball behind.
Kaepernick has a pitcher's motion in his delivery from being a baseball pitcher, and it's necessary for him to have that also because his arms are so long (almost 34"). Kaepernick is naturally a more accurate thrower than Locker... However, what also helps Kaepernick be more accurate is the fact that he doesn't have this "curl hop" footwork at the top of his drop... there's no way he could get by with having to overstride with 34" arms.
You see... everything that happens above the waist with a quarterback, is a direct result of what's going on with the feet... always has, always will.
Overstriding with your feet causes you to have a longer wind-up in your delivery... Long arms cause you to have more of a wind-up in your deliver. A quarterback can get away with overstriding more if he has short arms to off-set the difference.
The best quarterbacks in NFL history who were all in the 6'3"- 6'4"+, all had short arms no longer than 32" in most cases... anytime you can find a quarterback with good height like that, but with short arms, he's naturally going to have an exceptionally quick delivery.
Of all the Senior quarterbacks in this draft who have been measured so far, which one fits this profile the best?
Pat Devlin.. who's 6'3", but only has 31 1/2" arms.... it's no coincidence that Devlin also has the quickest, cleanest, most compact delivery in this class of quarterbacks.
It's a very interesting study.... Look at the best 6'4" or so quarterbacks currently in the NFL (Phillip Rivers, Peyton Manning, Eli Manning, Tom Brady, etc.) and look at their arm lengths compared to their height... they all have short arms to be that tall.