Arch, maudlin, or romantic dialogue only works with charismatic actors and competent direction, often where the actors play archetypal characters. See The Adventures of Robin Hood for that style done to perfection. ANH actually does a reasonable facsimile of this since the characters are properly archetypal (the rogue, the princes, the farm boy, the wizard). The problem is that the prequels have almost none of these elements. The charisma of the actors is buried under robotic direction, and the underlying characters are muddled and pale shadows of their archetypal counterparts in the OT. As such, the stilted dialogue is just another nail in the coffin.