So whenever an anime is turned into a live action there is always complaints about characters not having Asian actors play them. Now I understand anime are set in Japan but I dont see characters as being Japanese. Like Naruto I dont picture him as being japanese.
When the last airbender(terrible movie) came out I will agree the casting was absolutely terrible but what I didnt agree with was with people saying all the characters should have gotten asian actors. I mean the show is an american show and the movie was made in the US.
Same with Dragonball evolution(absolutely terrible movie) when Goku was cast as an white guy there were many complaints. But Goku isnt even from earth so why are people complaining when Goku may very well be white, not saying he is.
So I hope this doesnt come off as racist, which it probably does but I love Asian people lol, honestly I am not trying to offend anyone. I am from the US so I guess I see characters in a different way. If a movie is produced in japan then having japanese actors play roles makes sense but if the movie is made in the US, I would think characters would be played by American actors.
I think it really depends on what sort of adaption you're trying to make
The thing about Last Airbender is that it should have been more multicultural. In the series, and what helped it be really good, was the diversity, the different backgrounds and traditions of each nation. For that movie adaption, the fire nation probably should have had more Japanese actors since the Fire Nation seemed to take much from that culture. The same way the Water Tribes seem to be with Eskimo culture.
That's why there was outrage around putting two white leads in the role of Sokka and Katara. And it was made worse by the fact that the two were terrible actors.
I see myself giving a slight pass to Dragon Ball Z, though, since the world it takes place in is so vastly bizarre and different from our own. With dinosaurs still roaming the planet and having locations like "Capsule City" and the like. Plus, the main protagonists and many of the other characters happen to be aliens from another planet, so I can let it slide.
Now, one area I think that you can't let it slide as much are the shows that take place more in reality, what I mean by that is the anime series that actually take place in Japan. If they wanted to do a completely faithful adaption, then it would have to be set in Japan with a Japanese cast.
On the other hand, they could also use the source material as premise and have a complete western remake, like how The Magnificent Seven was based on Seven Samurai.
I think it all comes down to what the source material is and how much it aligns with our world. It also comes down to if the producers and director really love the source material or are just trying to make a quick buck.