Avery Brooks had a TV series back in the 80's, "A Man Called Hawk", which was a spinoff of the show "Spenser: For Hire". His recurring character, Hawk, got his own show after "Spenser" was cancelled.
Hawk was pretty cool, but he was the "quiet badass" kind of guy, which if you think about it, doesn't actually require a lot of acting range. Just have to look tough, kick some ass, and say cool things once in a while. Sisko was something like that, except you really expect a bit more character in a commanding role, which is why I had trouble buying into him. Oh, and he didn't really kick much ass or saying anything cool, either.