2000, I would probably agree on Luck being the first pick but my argument would be that Cam has the greater potential because of one particular thing. As you said, Luck has done it for 3 years in a pro style offense. A lot to be said for that. I look at what Cam was able to accomplish in one year in this league and how he progressed overall as a quarterback....and the progressions he should logically make at the next level.
In looking at his stats, Cam had that killer stretch of games agaisnt UK, Arky and LSU where he did it all and firmly placed himself atop the Heisman race. But you look at those games and the one thing that stands out is the rushing totals. He was approaching 200 yards in all 3 games. From that point forward, Auburn played a stretch that included, Ole Miss, Chatt., UGA, Alabama, South Carolina & Oregon. In those games, with the exception of UGA, in which he went for 151 on the ground, he was either bottled up more or Malzahn changed up the strategy. Either way, he threw for 17TDs and only 2 INTs during the stretch run. He had to become a far more complete QB and pulled it off with flying colors.
Again, it's possible that Luck would have been #1, but I wouldn't discount where Cam will be after he goes through his workouts for the pro scouts. Look what we thought of Sam Bradford and what he was able to do when asked to show his stuff.