Whoever the director is, I think it needs to be one that is focused on the characters. What was lacking in the prequel trilogy was development of the characters and their reasons for their actions. Rather than Palpatine just being a bad guy, why weren't we shown why he was bad? Rather than Anakin just saying "Hey, I want power, I'm gonna go all dark and stuff", we should have compelling reasons for his turn (and more than "hey I had a bad dream about Padme. Teach me evil stuff"). I know that Star Wars boils down to an epic about good vs evil, but dynamic characters would make the film a classic.
So due to that, I would steer away from directors who are simply going to make an eye-candy movie.