I don't care for him at all, I think it was stupid to create this extra character when Dooku could have filled the same role. The coughing thing is annoying as well
He was created to be the walking, talking action figure of the movie. See Darth Maul and Jango Fett.
And I've never heard about his cough before. I guess I'll wait and see the film, but it sounds kinda stupid. Wouldn't he fix/repair himself to where he didn't cough?