I always thought it was because of some inferiority complex. I mean if you look at Metal Gear, Final Fantasy or any other Japanese game with anime-type characterts, you will notice that the characters have perfect faces, perfect emo hair, mediocore nose sizes - not Caucasian big and not Asian small - but somewhere in the middle, you will also see the characters as being slim and tall - I think that it's just a part of the underlying fantasy but I can't help but think of some sort of inferioty complex, I guess it's the effects of westernization and globalization.