A lot of people disagree with me on this, but it's my opinion: The most disappointing performance overall from a series regular, from the front of the series to the back, comes from Avery Brooks. Too many of his episodes seemed to have been phoned in. There comes. A time. When you wish. Each sentence. Were not. Delivered. Like a bad. Shatner. Impression. From deep inside. A mayonnaise jar.
Who would I have preferred? I don't think there are many people who would disagree with me (even if they liked Brooks) that a superb Capt. Sisko would have been portrayed by Phil Morris
I liked Brooks most of the time, but I agree that this is true for many of his performances, particularly in "Far Beyond the Stars"
where he definitely channels Shatner at his worst in the final scene.
Morris did a good job in his few DS9 appearances playing aliens. I think he could have done well playing the captain...as long as people didn't have trouble taking him seriously because they recognized him from "Seinfeld"