Oh, so lets just run around and kill any remotely intelligent and loyal person the empire has. What kind of completely self-defeating logic is that? But okay, lets roll with the "Vader is still young and controlled by the dark side" argument. Why didn't he kill the Emperor then? Why would he pass the opportunity to grab all the power? He doesn't play the game ... by blindly following Palpatines lead? What?! That makes absolutely no sense at all! If he was fed up with Palpatines BS he should simply ignore him, not do exactly what he wants.