This is a series of posts at a blog called
Sociological Images that deals with how people of colour are used in advertising that's aimed at a white audience and I think it makes some fantastic points that can be compared to film.
I think we can all agree that M Night is not looking at this film in the wide reaching audience terms that the TV show did. We get a lead cast of all white actors with everyone else in the background or as villains.
This summed it up for me.
"I offer you examples of ads that include people of color in order to associate the collectively-held meaning of the racial minority group (i.e., stereotypical traits, the social construction of the group) with the product."
The only reason we have Asians at all is to give this thing cred as a martial arts flick. Take a look through, it's pretty interesting reading.