One great recurring theme Lucas has now set up that works well is the fact that Palpatine thinks in ROTJ that he can get away once again with tricking a group of people into their own demise like he did in ROTS. Yet of course, his overconfidence was his weakness.

I think one of the reasons there are so many continuity errors in the films is because Lucas seems to look mostly at the big picture; he looks at it as an epic, and forgets a lot of the smaller details that he sees as less significant. It's the things like the recurring themes with Palpatine that he pays attention to.