After Finn Jones has been cast as The Iron Fist for some reason there some controversy because they stuck to the source material and didn't make him Asian-American. Just because he is a master of martial art doesn't mean he should be Asian, its a weird stereotype which makes it more surprising by the anger some people of had about keeping this character faithful to the source material.
It doesn't make sense why they would make Iron Fist Asian-American in the first place, his Origin is that he is from New York and after some events gets taken in by the people of this mystical city called K'un L'un and trained by them for decades before returning to his city. I always believe that as long as it doesn't effect the character you can change the race and sex of a character but one of the main factors of his experiences in K'un L'un is that he is an outsider than he stands out to the rest of the K'un L'Un Warriors making him Asian-American takes away that outsider feel as most if not all of the K'un L'un Warriors would be of Asian origins and to have that contrast is what makes his experience more interesting.
But if they did do the race change its a double edged sword, the best example when they made The Human Torch Black, I had No Problem with Michael B. Jordan as the human torch but the amount of backlash that they had about him being black was ridiculous but it did happen so if they made Iron Fist another race just cause there will still be hate.
But the main reason I think making Iron fist Asian was pointless, there is already a Asian martial artist named Shang-Chi (the master of kung fu)
Who might appear in the Iron Fist series or have his own series as it has been rumoured also and if they made Iron Fist a similar race and argument could be made for them being to similar.
But they have cast a white for a white role which in my opinion was the right decision.