Yeah Cho is Korean, so if you said Korean I would have understood what you meant, I never heard anyone call him Chinese.
One Asian ethnicity playing another, I don’t have any issue with it, not very noticeable to me. For Sulu particularly, he was supposed to be a character for all Asia, the character was established as Japanese but Sulu isn’t a Japanese surname, so if a Korean or Chinese or Thai plays him, meh.
Park’s character, Hoshi Sato, was under-developed, the only outward hint of her ancestry being her name (source’s do say she was born in Kyoto, Japan, but that comes from the brief on screen flashing of a personnel file) which doesn’t preclude her being part-Korean. I think she really shined in the Mirror Universe episode where they actually gave her something interesting to do, she and the Black dude where terribly wasted and underdeveloped characters. The Black dude as helmsman of the ship could have been replaced with a rotating extra like post-Wesley TNG (other than Ro Laren, a shame she wasn’t in more episodes) and it wouldn’t have made any difference. Dr. Pulaski got more character development in one season of TNG then he did in 5 seasons, and probably more lines too.
I would not ascribe some kind of sinister “Star Wars Fanboi’s revenge” motive to Abrams , it’s was just horrible film-making from people who didn’t jive with the source material. Though some allege he put in Star Wars esque features in order to “audition” to be director for the new Star Wars movie, I could buy that.
“The Black Dude” from Enterprise is now on “General Hospital” playing a psychiatrist (caught in a love triangle with the Black Lady Police Commissioner and Finola Hughes’s Anna Devane, nevermind she looks old enough to be his mama).
If they were going to cast a Korean to play Hoshi, they cast the wrong Park. I would’ve gone with Grace, as she’s arguably one of the most beautiful Asian actresses working today. Although that’s still not enough to get me to watch that Battlestar: Galactica reboot or the Hawaii Five-O one. Jiminy Christmas, can’t anyone come up with original material for a new show ?
The worst attempt at Sato characterization was in an episode where she and the others were stuck in decontamination and she told the story about being charged with insubordination for striking an officer. This was taken almost verbatim from Starbuck’s backstory on the (hated by me) Galactica reboot.
As for a black helmsman, I watched every episode and don’t even remember him.