It might be overrated.
I didn't see Sith. I just couldn't manage to get my sorry ass to the theater for that last Lucas...I don't know what you call his creations anymore. The characters are just, ugh.
I think Orson Scott Card called Serenity the best sci-fi movie ever. Whedonites are generally starving, frothing at the mouth for new Joss material. And it's not mind-blowingly original in terms of sci-fi themes or ideas. And he's obviously lifting concepts from Star Wars, among other sources. But it's all sort of mixed together in a uniquely Jossian way.
I guess it's a matter of your tastes, priorities. I don't care enough about sci-fi to complain. I care more about the dialogue, characters. I actually enjoyed the pseudo-political, social commentary stuff in Serenity.