When it comes to scouting for the NBA Draft, players without a ton of "upside" are treated like they are as good as they will ever be, while players with a ton of "upside" are given the benefit of the doubt. From what I remember, Jimmer is as good a player now as Steve Nash was when he came out of Santa Clara. Nash has worked exceptionally hard to become who he is, and there is no doubt Jimmer will do the same.
There are three NBA players Jimmer makes me think of - Nash and Pistol Pete (as has been mentioned quite a lot) and Vinnie "The Microwave" Johnson, who you'll recall was instant offense for the Bad Boy Pistons. I think that Jimmer will very likely spend his career filling that role for a contender.