They posses everything that's looked for in the quarterback position, most notably arm strength, accuracy and poise. Assuming both reach their full potential, it's hard to envision them not being two of the best that the league has to offer. However, like any other rookie, they have their own issues.
Despite being the top two picks, both quarterbacks should look to improve on the following aspects of the game: decision making under pressure, pocket mechanics, identifying hot reads and understanding coverages.
Luck and Griffin's issues aren't significant, as they are still young and learning their respective positions, but they should be noted as areas that need improvement.
Decision Making Under Pressure
Based off what I've seen, I would say Andrew Luck has the upper hand over Robert Griffin III in this part of his game, but both need to work on their decision-making under pressure.
Both quarterbacks often try to make a play instead of taking the sack or throwing the ball out of bounds, and this leads to turnovers. One instance in Griffin's case came against Texas A&M (9:24 mark) in his Heisman-winning campaign, where Griffin took a snap and rolled right, faced pressure and threw the ball off his back foot down the field. The throw resulted in an interception and loss of possession.
In an ideal situation, Griffin would have simply thrown the ball away.
There's nothing actually wrong with the footwork of the two quarterbacks; rather, it's their tendency to get lazy with it in the pocket.
The former collegiate quarterbacks went flat-footed at times last season whenever they had too much time in the pocket. This led to slower deliveries because they had to reset and then deliver the pass, consequently buying defenders more time to break on the ball.
It's not a grand issue, as there are signal-callers in the NFL that have this same issue, most notably Tom Brady of the New England Patriots. However, it is something worth cleaning up, as both quarterbacks are perfectionists.
Identifying Hot Reads
Hot reads are essential to beating the blitz with the pass. What a hot read can be described as is a receiver shortening his route and sitting in a vacant spot so his quarterback can find him whenever a blitzing defender leaves his zone.
Unfortunately, both quarterbacks have had issues with this in the past, but that can be expected as they are young. Some quarterbacks still have trouble with this, namely Michael Vick of the Philadelphia Eagles.
Understanding of Coverages
Identifying coverages is difficult for every quarterback, especially when they are new to the NFL and lacking experience.
Luck found this out the hard way against the USC Trojans in his final collegiate season when he threw a nearly costly interception late in the fourth quarter.
Luck saw the play-side corner dropping deep and decided to throw the ball, only to see the cornerback plant and drive toward the ball, intercepting and returning it for six points.
It was a little easier for Griffin III to decipher coverages while throwing the ball, because Baylor utilized more spread formations than the Stanford Cardinal. However, he'll still have to make the adjustment in the NFL, where coverages get even more complicated and misleading before the snap, when defenses rotate their defensive backs late.
Rookie quarterbacks will struggle in the NFL early on in their career because they are still learning how to play the game despite the three or four years they spent in college.
Who will develop quicker?
College offenses today are comprised of spread formations, which has increased the pass attempts of quarterbacks but reduced the form of dropbacks and throwing distance. Consequently, the footwork of the passer has suffered, leading to many quarterbacks throwing poorly-placed passes because they are not rotating their hips and stepping through their throws.
Footwork, decision making, hot reads and understanding of coverages have all become issues for young quarterbacks going into the NFL. All four of these aspects are areas in which Andrew Luck of the Indianapolis Colts and Robert Griffin III of the Washington Redskins must improve as they develop on the job.