If she looks Vulcan, it's all a matter of makeup, and anyone can play her. If she looks half-human with Asian features, what is non-Vulcan in her Asian features? They both tend to black hair, and the eyes aren't all that different. Her blood is green, so the skin color will be done with makeup, too. Her mother's first name is Greek, so what percentage Asian is she, really? This is hundreds of years from now, and offworld. The racial blending could be vastly different from any 21st century human appearance. I don't see why the actress has to be Asian.