...that there seem to be few manga showing Japanese-looking people? Take Nabari No Ou as an example. This story is supposed to take place in modern Japan. Most of characters even have Japanese names. But many of them have blond(e) hair and non-Asian features.
I suppose the logical explanation is that in a black and white story, it would be really hard to tell the characters apart if they all had the classic Asian features, with dark hair and eyes. This also explains why it is common in manga for characters to have facial scars, special makeup, an eye patch, or some wacky hair color or 'do.
I certainly hope it is simply this, and not some sort of racism against one's own race that leads Japanese mangaka to largely avoid showing Japanese faces in their manga. I know that sort of racism from my own experience. As a teen I caught myself considering buying some sort of color-correcting foundation, which would supposedly make my olive skin look less green and more...neutral...like some sort of northern european ideal that so many people feel compelled to strive for.
Dear God, let us all love ourselves as we are.