Is there any way you could play up the jealousy of Anakin over Obi Wan about Padme? That was sort of played down and Anakin's more irrational fear of losing her played up.
And also, when the Emperor tells Vader that he killed Padme, I think it would be cooler if he silently stares into the void instead of cheesily yelling "NOOOOO!"
Those 2 things and taking out Padme's death would make the movie much more satifactory.