Personally, I think when the character keeps being mistaken for a VULCAN, demanding a Chinese actress play the part is absurd. <SNIP> Perhaps the writers should make more of a point about her Chinese looks, and stop having people think she's a Vulcan.
Is there any particular reason the characters would react to or make note of her Chinese-Human heritage more than her Vulcan heritage? I mean, looking like you come from Asia probably means nothing to the people in the STU -- it probably doesn't really register with them in the same way that being Vulcan or being Andorian or any other given species would register. Take away the pointy ears and eyebrows, and they wouldn't look at T'Rys and say, "She looks Chinese," they'd look at her and say, "She looks Human."