Winston has shown that he makes terrible decisions when a defense puts pressure on him. Since FL ST. is so good he has often had so much time where he can sit back and make the throws, but as we saw in games (Florida being the most recent) that his decision making becomes bad and he throws bad passes that turn into picks.
Hes going to be facing defenses in the NFL that come up with fancy blitzes and schemes to defeat him and the big question is will he make the adjustments. His release is also a question mark. His behaviour off the field is not as simple as you make it out to be. Who's to say a guy with the trouble he has had making 5 million is going to turn it around. If anything he could turn into Vince Young.