Some info about KO from a Purdue alum (1997-2004 when Drew Brees and Kyle Orton were in school).
I agree with the general notion that KO is an above average NFL QB lacking the "it" factor, but I firmly believe he can become a great QB with "it", put in the right situation - pretty much true for every QB, unfortunately KO is still waiting for his.
First of all, KO has all the tools, hardware and software. He was great in college (and high school). He's the only Purdue QB starting 4 bowl games, something Drew Brees, Bob Griese, and Len Dawson never did. KO started his senior year as a Heisman hopeful and considered by many the "surefire No.1 pick" for 2005 NFL draft, but in mid-season a few mishaps and injuries hit him, derailing Purdue's dream season and slipping him into late round.
As a rookie, KO started 15 games for the Bears, going 10-5. He was asked to be a game manager behind a great defense and he did his job. Then Grossman the "franchise QB" came back from injuries. KO didn't start again until two years later, when Bears finally gave up on Grossman. In the first half of 2008 season, KO played great and was considered a MVP candidate (go googling if you didn't know that), but then the injury bug hit again, and the Bears defense lost 4 games in waning minutes (go look at those game recaps at ESPN) but all blames went to the QB... Traded to Denver off season. Started 6-0 in 2009, gaining loud praises, then somehow things went south. In 2010, KO played 13 games, 3500+ yards, 20 TDs, 9 INTs, 1 fumble, not as bad as people made him out to be. Those who call him a turnover machine are outright donkeys.
Now, what has prevented KO from being "franchise"? He has adequate arm and accuracy. He has the intelligence to read and beat defense. He's a hard worker with leadership (at Denver he's a captain elected by his teammates). Nobody can deny those. The only thing he has lacked is consistent support from higher up, not killer instinct. Having someone constantly looking over your shoulder, having your coaches constantly doubting backstabbing you either because you were drafted low and cheap or they are looking for a scapegoat, is not something many QBs can overcome, and you will get conservative and hesitative in your play, which in turn can affect your confidence and consistency. KO was not this way in college at all. He was as much a gunslinger as Drew Brees (that being said, very few people on this planet are as mentally tough as Brees).
I think KO and KC are a perfect match in element and style. Give him a commitment, let him go loose, and you will get a Len Dawson II in return. I'm sure of it.
Fans always get excited about drafting a new QB, but always ready to ignore the truth of the matter in drafting a QB. This year nobody other than Andrew Luck is much beyond the likes of Leahart, Quinn, Young, Russell, Carr, fans certainly forgot fast how highly touted those guys were out of college. As a matter of fact, most Saints fans in 2006 wanted Young or wanted to wait for Quinn the next year, there you have it.