You don't think the moral and ethical dilemnas Star Wars deals with are intellectually meaningful? Besides, even if it wasn't, I think your definition of science fiction is too limited, or too broad, however you want to look at it. If it required science (explained) there would by any number of movies which wouldn't count. Back to the future, Starship Troopers, Matrix, etc... If it need only be intellectually respectable, then you could consider Pulp Fiction science ficition. I think instead good science fiction needs only be scientific insofar as it tells a story that has a central plot element which is only explainable through science - i.e. it is set in space, or it is set in a "matrix".