I think you're probably right about Lucas. I mean, he has the Rebels use the Ewoks' belief that Threepio is a god to get the Ewoks to fight and die for them - and it's cute. The characters can't spare so much as a line wondering about ends and means?

And yes to the over-the-topness of Palpatine's face distortion. I figured he got that way by RotJ because he used the dark side to extend his life too long and his body was falling apart, but no, it turns out that evil makes you ugly.