Brandy is a vocalist, not a producer. I see nothing w/ her adopting the sound that best showcases where she is emotionally. A painter doesn’t have to make the canvas and the brushes.
Mariah isn't a producer either, but you see her stamp in all of her albums, and most of them have substantial differences. Memoirs was all Dream but still was a "Mariah" record; HE adapted to her song structures, thematics and vocal habits, etc., not the other way around. He didn't drown her in his sound. Her albums are consistent and despite the vocal decline, you see and appreciate Mariah's essence in each of the records.
Brandy bestows herself to the producer to the point of losing that "essence" to please them, and that's why B7 is melodically modest despite that being one of Brandy's strong points since the very beginning. She's admitted to be insecure and we all see that in every long ass break between albums, and cannot decide for herself which songs are "it", but a seductive, persuasive producer does it for her so he will always put his own vision for the record instead.
I know Bran has the potential to be way more involved in her music because the sole aspect of her vocal knowledge makes her super capable. But her insecurities get in the way.