Star wars is not sci-fi, it is FANTASY. It's always been about cool planets and cool aliens and cool ships, Star Wars is very much about style. And I suppose you real chinese emperors and european nobles looked silly too. I think the OT costumes look silly, why would a princess wear a white sheet and a city administrator wear "dress down day" clothes with a cape? The OT costumes made no sense. The ornateness of the PT costumes re more realistic than the thrown together OT costumes.
Star Wars cannot be simply categorized as being only fantasy or only science fiction. It is both.
The OT costumes worked fine. They went so far and no further. The PT costumes go further, much further, as you can see from the ridiculous getup they put the queens of Naboo in. I'm sorry I don't see what's so senseless about the OT costumes. Leia's costume seems pretty reasonable for a princess. I think Lando's is pretty reasonable for a dandified city administrator in a science fantasy film. Neither costume makes the character look like an absolute idiot like the Naboo queens' costumes do. And I have to say I really fail to see how the PT costumes are somehow more "realistic" than the OT ones.
I see a lot of making excuses here for something dumb and pretentious in films most of us dislike. I don't get it.
As for your Chinese emperor, I'm sorry but that's more moderate than what they put poor Padme and the other queens in. Also, dressing monarchs in particular in extreme ways has a lot to do with society's viewing monarchs as superior to the general populace. I would expect an advanced society (Naboo is supposed to be especially enlightened) that ELECTS its monarchs from the general populace to be a bit more advanced in its thinking (such as not viewing monarchs as so superior) and maybe not dress their monarchs in such a worshipful manner. There is no call for Lucas to have his democratic enlightened paradise world's monarchs exceed the excesses of Earth's monarchs of earlier eras. The intention seems to have been similar to the cgi backgrounds -"Let's put on a big showy show to show we can". It was dumb and destructive.
Btw, I hope that people understand that I'm not just talking about clothing. Hairstyles and makeup are very much part of the picture and particularly relevant in the case of the Naboo queens.