Monk can fix his issues with the daily work on the NBA level much easier than another college season. He has the "it" factor.
Briscoe, Hump, Wenyen - no reason whatsoever for them to consider leaving.
Monk needs to get smarter and more mature. His talents will only get him so far at that level. I know I'm talking to wall, not you, because he is definitely going pro, but he needs to come back another year.