Now make no mistake: I fully agree with Robert Griffin III winning the Heisman over Andrew Luck. If you want to know why, head over to Rivals or Scout and compare recruiting classes for those programs over the last 5 years. If that is too boring for you, then consider it this way: where going into bowl season Stanford had the #24 scoring defense at 20.3 points per game, Baylor had #109 at 35.7. So, Griffin III and Baylor won 10 games with a defense that gave up 5 TDs a game ON AVERAGE, and did it against the #8 schedule in the country. Meanwhile, Stanford won 11 games against the #45 schedule.
But that is the Heisman race. The Heisman race doesn't go to the best player. (If it did, defensive players would win it A LOT more.) It goes to the most outstanding player, a different criteria. Luck is a better college player than Robert Griffin III, is a better NFL prospect, and for the first few years of his career will be a better NFL player. Yes, Robert Griffin III has more "upside", but consider Andrew Luck's upside. Some regard him as similar to Peyton Manning, except a good bit more mobile. Others regard him as similar to Drew Brees, only taller and with a stronger arm. Either way, isn't "possibly better than Peyton Manning or Drew Brees" upside? Even if you take the argument that "sure thing" is better than "upside" with the #1 overall pick at QB (see JaMarcus Russell's "upside" versus Matt Ryan's "sure thing", they didn't come out in the same year of course, but the point is still good) the fact is that Andrew Luck's "upside" is significant.
There are other considerations. The offense of the Colts and the Stanford offense are so similar that were the Colts to part ways with Manning immediately, they could put Luck in and run the exact same thing on opening day. Even if Manning stays a year or two, you could just replace one with the other and not skip a beat. Not so with Robert Griffin III. While the Michael Vick comparisons are way off-base (and stereotypical) the fact is that Baylor runs a shotgun-spread offense that does not translate well to the NFL, plus Robert Griffin III's skill set AS A PASSER is far different from Manning's. Griffin III would require a completely different offensive system, likely with new personnel. Even if Griffin III had the same risk level as does Luck - and he doesn't - that alone would justify taking Luck over Griffin III.
As it is, the risk level is totally different. With Luck, there is no risk. Other than the fact that there is no such thing as a "can't miss player", there is almost no chance that Luck won't go to several pro bowls. Even the main argument - the suspect talent level of Pac-12 defenses - is mitigated by the lack of talent that Stanford had at wide receiver (their best offensive formation was a 3 TE one). Meanwhile, regarding Robert Griffin III, I will say that he is the best shotgun-spread QB prospect since Drew Brees. The problem is that no shotgun-spread QB has really succeeded BUT Drew Brees in the NFL, despite major college teams running them for going on 20 years. The high profile prospects like Tim Couch and Ryan Leaf have been busts, and perhaps an even bigger problem: the many guys who went in the later rounds haven't worked their way up as starters.
That said, Robert Griffin III has a strong chance of being good, and a chance to be great. But Andrew Luck will almost certainly be good, and actually has a better chance of being great than Robert Griffin III does. Yes, Luck has a better chance of being a Hall of Famer who wins 2 Super Bowls than RG3 does. RG3 merely has a better chance of being a Joe Montana type who wins 4 than Luck does. Big deal! The issue is that the chances of RG3 being Joe Montana are so small, why bother shooting for it?
The Colts will take Luck, and they won't waste a lot of time discussing it.