What 'problem'? FF character faces being based on Asian faces is a 'problem'?
And Chinese are Asians.
It's not a "problem", but non-Asian customers might feel alienated if every single one of the characters have Asian facial features, the same way that a whole caucasian (or any other ethnicy) cast might alienate customers from other races.
I know it's silly, and personally I can relate perfectly to any character's emotions and predicaments regardless of gender, race or even species, but market figures are there.
If I remember well, Sazh wasn't very popular in Japan because he looked Afro-American, hence the customers had a hard time relating to him, and in general, people in Japan didn't like Snow because he was "too American" for their taste.
So, you see, these two characters were a problem for the inner market (in fact, they don't know what to do with Sazh in LR and it shows), but they are perfectly fine for the exterior.