Watson's a great college QB but his 'style' won't convert to NFL greatness IMHO - his scrambling ability is far superior to his arm and in the pros it's the ability to throw the football that ultimately determines your value.
Somebody will give him a chance but I'm not convinced he's 1st-round material, much less #1 ... the guy they ran off to 'ole Miss has more of an NFL arm than Watson. That's not in any way a knock on his ability to influence a college football game.
Regarding his 'heisman' chances my opinion (and it's only one opinion) is the guy at Stanford is slightly better than Watson ... his performance in the Rose Bowl was superior to Watson's effort against 'Bama ... almost 80-yards of Watson's 'total' offense in the NC game was that give-away last drive 'Bama allowed letting clemson score to make it look much closer than it was with 12 seconds left after the game was long decided.
Both those guys should be 'in it' again in 2016 and it's certain someone else will get in the picture, too ... maybe Fournette, who knows. I remember listening to Fournette after the LSU game and he is a VERY impressive young man ... reminded me a LOT of Marcus with his humble approach and respect for his teammates (and kind words for SC). College football benefits from guys like those three ... all of 'em are winners.