Brown was good in terms of developing Cov, TJ, Noel, Saric, and Grant. Not so good with Okafor, Fultz (special circumstances?), TLC, Korkmaz, McDaniel, and most of the other d-leaguers and borderline 10-day players. I think it's a fair criticism that players have not improved as much under him as we would hope.
Frazier and Ish Smith were noticeably better after moving on. If Saric improves a lot it would be pretty telling, but so far he seems to be about the same guy.