1) One of the most successful movie franchises I can think of is The Fast and the Furious, which manages to have a very ethnically diverse cast without shoehorning it down our throats that it's ~diversity~
2) Racial representation in the media is pretty poor, but Asian actors have it worst than most. There's a great line in an Aziz bit about him hoping that it gets to the point where he can like an Indian character on the merits of the character, and not just because it's the only one for ten thousand miles. We want to watch people we can identify with!
3) If you don't think that cis-het whitewashing doesn't exist, then you're delusional. Let's look at some castings where Asian characters are replaced by white actors, shall we? Let's see...we have Scarlett Johansen playing The Major in Ghost in the Shell, we have Emma Stone playing Allison Ng in Aloha, we have Tilda Swinton obviously playing The Ancient One, we have all the white people in The Last Airbender, Tom Cruise in Edge of Tomorrow completely replacing his novel counterpart, Keiji Kiriya, Mickey Rooney as Mr Yunioshi in Breakfast at Tiffany's, and my personal, heart-crushing worst/favourite, Fisher Stevens as Ben Jabituya in Short Circuit.
4) This is nothing new. Everything, including Hollywood, privileges white people; whether it's whites-only on Friends or Girls or Elizabeth smurfing Taylor as Cleopatra, or Ben Kingsley in his best Maori geddup, or whatever. And on the flipside, my boy Cliff Curtis has to play terrorists and gangsters and criminals of every shade of caramel, chocolate, and toffee, and the only recent time he gets to be Maori and not a homeless guy/rapist/criminal is when he's being chased by zombies (I'll take what I can get).
5) Here is a popular article if you would like more examples.

I probably won't see Dr Strange, I'm not very attached to the comic. One comic I am attached to is Spiderman, so it's even more of a shame that we're stuck with a third smurfing whitey spidey reboot, instead of going down the Miles Morales route.