Ape, you've done your homework, I enjoyed the information in your post. The only thing you are overlooking is the "winning" edge. The NFL is a business. Businesses look at the bottom line. In the NFL, the bottom line is WINS. The other stuff you mentioned are indicative of how many games a QB can help you win, but nothing speaks more loudly than a 37-2 college record. NOTHING.
Am I predicting Leinhart will be a great NFL QB? No of course not. As an ND fan I hate him and would love to see him flop. However this debate was based on his DRAFT POSITION, and there are PLENTY of LOSING NFL TEAMS that have nothing to lose by taking a leader/winner early in the draft. Because of his ability to win games, some team will take him in the top 5 of the draft.
if you recall, nobody said he was good enough to start when Palmer left and they were dead wrong. And you are right, he had a great supporting cast and some great receivers in his tenure at USC. But the last time I checked football, even in the NFL, is a TEAM sport and other players MUST contribute to ANYONE's SUCCESS! That argument is overrated.
The bottom line is that staying at USC and going 11-1 could not have hurt Leinhart. If anything, if as Sex Ape says, and Leinhart was LACKING in some fundamental QB qualities, then another year in college could only HELP his development