Yes, Star Trek TV series is really kitsch now but they found good ideas. You are true : on the opposite of Star Trek and Galactica (and others), Star Wars never became old and kitsch, the first episode was issued in 1978 or 1979 I think and it is still so good, the designs are not ridiculous, the team did an incredible job ! Only some clothes are perhaps too basic (and then too complex in the newest episodes ?).
Yeah Star Wars was pretty much perfect with the character designs. Rebels and Imperials had a very distinct style and it helped the movie quite a lot. Trek was probably a bit too "standard", going by stereotypes, as Federation uniforms were too formal (some were just impractical to wear) and aliens were too weird (Klingons looking like a bunch of homeless guys).
New SW episodes just lost everything of all that by introducing overly complex character designs. It's funny that Episode 1 was the best one of the bunch, as it didn't go to the extremes.
Original trilogy having some of the clothes and ships very basic didn't help the new trilogy either, as the technology got better and it's impossible to tell yourself that the ships from Clone Wars era are older than the rusty Xwings