Yeah, having a vacuum of cool is indeed impossible. Computers do a better job of being a villain than him. The Reapers of Mass Effect are just as ambiguous in their motives, but they are a sight more evil than the silver haired queen.
Though I agree that the Master Chief is overrated, he is not quite as dull as indicated. In the games he is, but the novels expand upon his character. Still nothing to write home about, but at least he's better than some other protagonists.