I don't think it's wrong. For good or for ill, race or ethnicity (whether perceived or actual) is probably the first thing we notice about other people except for gender.
How you'd go about presenting this will be a function of narrative viewpoint, imo. If you are writing in a character pov (first or limited third), the viewpoint character's own norms and biases will drive how someone is described. One white person from the US may see someone of East Asian descent and think of them as "a Chinese guy," another might think of them as "Asian." (or even, if in my mom's generation, as "Oriental,") and another might try hard to avoid using a racial marker at all, even within their own head.
It is challenging, though, because if your pov character is someone who would refer to a person of East Asian descent as "oriental," even though that's offensive, some readers may assume it's the writer's bias, not the character's. And some people will look at a person of another race and see nothing but the race and not their individual traits. That's why it's important to make it pretty clear where the narrative is coming from.
If you've got an omniscient narrator, you can be more neutral in how you describe someone's ethnicity. Then it will come off as pretty lazy if someone is only described by their race. One mistake some (white) writers do with omniscient is to assume that whiteness is the neutral norm and to only mention the race or racial features of PoC.
It gets more complex, of course, if you're writing speculative fiction set in a universe where the countries and continents we use to designate ethnicity don't exist. Saying someone looks like she is of "Esuvian" heritage doesn't tell a reader anything.
There are some blogs and websites that discuss techniques writers can use to describe racial characteristics without being cliched or offensive.
http://writingwithcolor.tumblr.com/Navigation
http://www.mitaliblog.com/2008/10/ten-tips-about-writing-race-in-novels.html
http://nkjemisin.com/2010/02/describing-characters-of-color-3-oppoc/