College players have flaws, that doesn't mean they will always be flaws.
I honestly believe that Simmons is as good a prospect as we've had since Anthony Davis in 2012.
And Steph Curry wasn't Steph Curry coming out of school either. Here's his NBADraft.net writeup which is pretty in line with what people thought about him.
http://www.nbadraft.net/players/stephen-curry 30 - Stephen Curry - Davidson
Birthday: 3/14/88
NBA Position: PG/SG
Class: Junior
Ht: 6-3
Wt: 181
Hometown: Charlotte, NC
High School: Charlotte Christian
NBA Comparison: Mahmoud Abdul-Rauf
Weaknesses: Far below NBA standard in regard to explosiveness and athleticism ... At 6-2, he's extremely small for the NBA shooting guard position, and it will likely keep him from being much of a defender at the next level ... Although he's playing point guard this year, he's not a natural point guard that an NBA team can rely on to run a team ... Struggles defensively getting around screens ... Can overshoot and rush into shots from time to time (vs. WV) ... Hasn't had to deal with getting benched due to poor performance (shooting) which has allowed him to shoot through any slumps. Will have to adjust to not being a volume shooter which could have an effect on his effectiveness ... Doesn’t like when defenses are too physical with him ... Not a great finisher around the basket due to his size and physical attributes ... Makes some silly mistakes at the PG position. Needs to add some muscles to his upper body, but appears as though he'll always be skinny ...