The sister thing is really the only thing from the trilogy that goes clunk for me. It's pretty clear at the end of Empire she loves Han, and Luke is cool with that, he's got bigger problems. That was plenty good for resolving the triangle. Can't Leia be The Other simply by becoming the full George Washington-leader of the Rebellion?

In general, I think the trilogy is very much in line with what was set up in 77. Luke learned the ways of the force and became a jedi like his father, Han got Leia ("you think a princess and a guy like me..."), the good guys won, and everyone lived happily ever after. I mean, if the story didn't shift gears a little and the tone and the status quo never changed, that's called Star Trek, and well, sucks to that.