Got distracted from posting this due to the holidays.
There was a lot of controversy over Marvel's choice to cast Tilda Swinton as the Ancient One. (In meta they said she's supposed to be "Celtic" but nothing is said in the movie to explain why a character that has always been Asian is suddenly white).
The director said he wanted to "avoid stereotypes" - but making the character female, alone, would have fixed that. (And then there are the people who think Disney/Marvel should have thrown away the entire lucrative Chinese market by sticking to comics accuracy and setting it in Tibet. Which is another issue).
But then there's the thing they did right.
Wong was ably played by uh, Benedict Wong (Sorry, I can't help but be amused at casting a Wong to play a Wong even if it's close to casting a Smith to play a Smith). The actor is a Brit of Chinese descent who also showed up in The Martian and played Kublai Khan in a Marco Polo TV series. He's not hugely famous - and I'd argue that's because of the lack of opportunities for Asian actors not any lack of talent.
In the comics, Wong is Stephen's manservant. He's mostly seen opening the door, making tea and occasionally fetching some requested book or item. He's two-dimensional and frankly a stereotypical Chinaman (he's supposed to be Tibetan, but...) And, of course he knows martial arts, because everyone in China knows martial arts.
Movie Wong? Movie Wong was something quite different.
We first see him taking over as the Ancient One's librarian after the previous librarian is murdered by the bad guys.
He is a master sorcerer in his own right, but not shown as being particularly powerful compared to some of the others. Instead, he is portrayed as a brilliant magical theoretician. If he doesn't know it, he knows which book you can find it in. Although reserved and, yes, a little bit inscrutable, he has a definite personality. And while he is not a martial artist, when the push comes to shove he's pretty handy to have in a fight. (He uses the Wand of Watomb, by the way, in the final fight).
In other words, the movie whitewashed one character - but also fixed another, which goes a long way towards making up for it.
(It was also quite fun but had some pacing issues. They overdid the training sequences. Ah well).