I don't have that problem with Dune because a) to my mind the Atreides society is almost as alien and barbarian to me as the Fremen, he's not One Of Us and b) I do think that the fact that he's the Messiah makes a huge difference. The worst case subtext is "He's better because he's white!" - that any fine upstanding white man would naturally rise to a position of leadership in a primitive native society. Paul is clearly unique and supernatural, so that worst case analysis is ruled out.