If you ever wanted proof that college football talent doesn't always translate to professional football success, just take a look at the history of the Heisman Trophy.
The Heisman has been awarded 78 times to 77 different individuals (Archie Griffin won it twice at Ohio State in 1974 and 1975.) Of those 77 winners, only 16 of them went on to be the No. 1 pick in the NFL Draft.
Johnny Manziel was the 2012 Heisman winner and it looks like he will enter next year's draft, where he is definitely a top 5 QB prospect. It will be interesting to see whether he wins the award again this year, though it's looking like Florida State's Jameis Winston will win it. Manziel has the intangibles you look for in a quarterback, specifically the ability to make big plays out of nothing. He has good arm strength, can run well, is accurate, and looks all over the field. The only knock against him is his size, standing only six-feet tall.
Looking at the 10 Heisman winners prior to Manziel, we can see that winning the trophy doesn't always translate into becoming a great NFL player.