The thing about "whitewashing" in a movie (casting nonwhite characters as white) is that it's a commercial decision. Let's pander to the lowest common denominator and maybe we'll get a few more people into the theater. As a friend of mine said when people complained that a Hunger Games character, who was Black, was played by a Black actress, because they hadn't figured out she was Black when they were reading the book: "I don't know what's more upsetting, the racism or the lack of basic reading comprehension."
But it can be interesting to go the other way, to cast a traditionally white character as non-white. Because, in a lot of cases, the default choice is for all characters to be white (and straight, and in some genres, male) unless the plot demands they be something else. The fact is that for some characters it matters and for some it doesn't. Nick Fury and Alicia Masters were white in the comic books, but there's nothing about the characters that demands that they be white (unlike, for example, Bruce Wayne).
Chris Claremont, a seminal writer for the X-Men comic book early on (back when there was only one X-Men title 🙂 ), used to get mocked because, whenever there was an idea for a new character he would aways ask,"Is there any reason this character couldn't be a woman?" Which is rather mechanical solution, but when pretty much all solo books had male heroes, and superhero teams were all either all male or male with a token female, sometimes you have to hammer at things to loosen them up a bit.
There's a book nowadays called simply "X-Men," and team it's about is all women (and, so far, none of the characters has even commented on this). Comic books these days, in general, are pretty evenly balanced on this question (and, as I said before, it's interesting that the title which carries the tag "Earth's Mightiest Hero" is about a woman).
Of course, if you want to revisit the old days for some reason, you can see the Avengers movie. 🙂
As I said on Maggie 's blog: "...I do think that you can’t just take a character and change his or her race (or, for that matter, change their sex or preference, or their religion). I’ve tried this with some of my characters, as a mental exercise, and it’s been interesting. You start to see what defines characters (and what doesn’t — the areas where the flexibility is). You also come up against the fact that not everybody has access to the same types of life experiences. Which is not an argument against diversity, just against the idea that characters can simply be flipped in one direction or another."
The Hollywood remake of Let the Right One In (Let Me In) was pretty good, but it as nowhere near the original, and one very particular annoyance was that [spoilers!] the sex of one of the characters was changed, making it a pre-teen straight romance (with vampires), instead of what it was in the original (and the book), which was a pre-teen trans love story (with vampires). A lot of people saw the original without picking up on that, which is fine, but for those who did get it, it added a whole additional layer of meaning to some of the scenes. The filmmaker tried to pass this off as a detail, but I don't think a character's sex (or race, etc.) is just a detail, especially when that "detail" is being changed because of the danger that somebody, somewhere, might be offended.
Theater, being a less literal medium, has more flexibility than TV or movies. Lea Salonga can play Eponine in Les Miserables without Eponine being Asian (which she clearly isn't, since we see her parents and it wouldn't make sense in terms of the story anyway). She's just an actress from the Philippines playing a French girl. Many actresses have played Hamlet, and I was just reading about a production of Julius Caesar with all the roles being played by women (and one of Orson Welles' earliest successes was an all-Black "voodoo" production of Macbeth).
In books you have a flexibility that you don't have in movies, television, or even theater: to simply not say what race a character is, or to introduce a character and to delay the information, as I talked about here. You can even, as Sarah Caudwell did in her excellent mysteries, not reveal the sex of your narrator.