I mean, Tovar and McMahon appear to be developing just fine, I don't see anything alarming with the handling of Rodgers or other young players either. I don't watch the Rox closely so I don't know for sure but to me, Black is waaaaaay down the list of problems currently plaguing the Rockies.
Of the four major league sports in North America, coaching appears to have the least impact in baseball. Sure, a phenomenal manager like Bruce Bochy can have a huge impact, as can a truly awful one like Mike Matheny. But overall I don't see anything that's convincing me that Bud Black is actively holding the franchise back (we all know who is).