The worst I would say about Rick Berman is that his tenure was a mixed bag.
The positive: I liked all four spinoff series. They had charismatic casts and generally took a much more serious approach to continuity and consistency than the movies did.
The negative: Berman is reputed to be the executive who discouraged emotion and melody in the episode music scores, often resulting in a generic ahhhmmm note to tell you when the commercials were starting. Blah.
Overall, the franchise could have done a lot worse!