Akira. The Hunger Games. The Last Airbender. Recently, there's an upheaval by fans on the casting calls of the said films. Here's my perspective on the matter:
One of the problems is the audience's interpretation of adaptation. There's a lot of ways to "adapt" one media into another, and foreign properties (which makes The Hunger Games the exception as it's not a "foreign property", although it does feature a character with olive skin) are even trickier. This is an oversimplification, but foreign properties are usually adapted in one of two ways:
1) Theoretically remaining faithful to the source. If the original story is set in Japan, the adaptation is also set in Japan. Arguably The Last Airbender falls into this category (yes, it's a fantasy world, but the fantasy world contains a lot of multi-cultural elements that is obviously neither USian or European).
2) Appropriating the setting to fit the current culture but theoretically retaining the elements that made the foreign property unique. The Ring for example takes place in the US, not Japan.
Now let me discuss 1) as that's simpler. While there is some room for leeway, for the most part it's appropriate that the film uses actors and actresses that represent the culture of its characters (i.e. if the character is Asian, get an Asian actor). Not that it's as clear-cut as that. For example, personally, while I enjoy seeing Ming-Na Wen or Pat Morita or Lucy Liu or Mako Iwamatsu, I dislike Hollywood's "recycling" of these actors, especially for parts that aren't necessarily representative of their culture. There's a big difference between Japanese, Korean, and Chinese for example, but Hollywood lumps them into this unified category so that Chinese actors play Japanese parts and Korean actors play Chinese parts. It's better than the alternative--Caucasians playing a Korean for example--but hopefully there will come a time when the role calls for a Chinese actor, Hollywood actually gets someone Chinese, and not just one that looks Chinese.
Now when it comes to 2), the film producer has more leeway. Various countries like the Philippines, Korea, Taiwan, India, etc. have made films using foreign properties. In those instances, the actors come from their respective countries. If the Philippines were to do a film adaptation of Batman for example, we're definitely going to hire a Filipino, not an American. (In comics, another example of this is Spider-Man: India, or even the Japanese live-action adaptation of Spider-Man.) So in the case of Akira, I don't know what track Hollywood is taking it. If it uses 2), then there's some leeway for them to cast a non-Japanese actor, but it will definitely feel out of place if they retain the Japanese names (why do they have Japanese names if they're not Japanese???). Having said that, Hollywood has one glaring problem with regards to 2).
Hollywood is making a film for the US. Hollywood tends to cast Caucasians for most of their roles. Unfortunately, the US is not comprised of Caucasians. It's a melting pot of various races: African-American. Hispanics. Asians. Indians. So when making a film adaptation, even when using the 2) model, why are you limiting your casting choices to Caucasians?
When Saban for example adapted the Japanese show Kyoryu Sentai Zyuranger for American TV, it's understandable that Mighty Morpin Power Rangers would feature exclusively American actors (as opposed to Japanese). However, one good thing about the show is that it featured actors like Walter Emanuel Jones and Thuy Trang. (Of course the bad thing about the show is that it conformed to stereotype in terms of the color scheme. The African-American actor as the Black Ranger? The Asian actress as the Yellow Ranger? Really?) Similarly, that's why I approve of Idris Elba's presence in the upcoming Thor movie. Look, the Thor movie isn't about Nordic culture; Thor is about Nordic culture filtered through the lens of its American creators (Marvel Comics) as well as containing elements of fantasy and science fiction. It's not such a big leap of faith for the cast to include a Black British actor since this is an American production.