"Here's the thing. The great thing about anime is that it's ambiguous. The features of the characters are an intentional mix of all features. It's intended to be ambiguous." - M. Night Shyamalan on the casting of The Last Airbender
Here's the thing...if you really believe that, Shyamalan, is it just a strange coincidence that all of your protagonist leads turned out to be white? And that the only Asian lead you cast happened to be the villain? The thing is, if you're going to play the "racially ambiguous" card, then one of the things you should do is at least cast people that look like the characters in the show. Most of the people who are (or were? you know, before casting fail) going to watch this are fans of the show. They're interested in this movie because they want to see these characters that they love come to life. And part of that is how they look.
With racial ambiguity, I totally get the casting of Aang. Aang was short and pale and the defining characteristic is that arrow on his head. Check, check, and check. There's at least some resemblance between Aang and the kid who's playing him. But there's absolutely no resemblance between Katara, Sokka and the kids who are playing them. I'm not saying they should be twins, or that they even need to be Asian. But couldn't you have at least found someone darker than computer paper? Apparently finding dark skinned/Inuit/Asian looking people to stand around in the background.
I just find it incredibly irresponsible. I'm not saying that Asians have to saturate media and pop culture. But this "Avatar: The Last Airbender" is a children's show. All sorts of kids watch it and are probably looking forward to seeing the movie. But how strange must it be when you can identify aspects of your culture on the big screen but no main characters who look like you? How confusing must it be to have the picture of the characters in the animated series--the ones who look like you--in your head, but when you see the live action movie on the big screen, they don't look like you anymore?
I love "Avatar: The Last Airbender." It's one of my favorite shows and part of that was because that finally here was a show where I saw characters that looked like me with a cultural background that I could relate to. Is it so wrong to want that same feeling to translate to this live action version of it? This isn't the first case of "racebending" in films. The last really prominent one that I can remember is "21" about the group of Asian students at MIT and then all of a sudden the main characters are white on the big screen. Is it so wrong to want to see a big-budget/blockbuster movie where there's a main character who looks like me? One who isn't a villain or comic relief? Is it so wrong to want to identify with something in pop culture today?
Hollywood loves to exploit Asian culture but apparently only when there are no actual Asians involved.