I think people are laughing at the thread, but it did seem like Brooks was replaced in Season 4. I mean he lost the hair, other than the beard, but grew a whole new level of confidence and actually became rather badass. It was a nice and welcome transition for the character and made him into a really great captain.
I think the confidence stated coming with the addition of the goatee...er, van dyke! It seemed to coincide with better writing for Sisko too (and better writing all the way around).