We even had a black Alicia Masters in the last FF movies!
Oh, good catch. Can't believe I forgot her.
And of course Black Panther is the hereditary monarch of a sub-Saharan African kingdom, so there's a specific reason for his ethnicity. There's absolutely no reason why Johnny Storm or Kingpin or any of the others have to be white. Sure, that's the way it was originally done, but then, Sue Storm was originally weak and passive and the men were condescending to her, because that's how women were seen in the '60s. Should we be slavishly faithful to that as well? The good thing about modern adaptations is that they're reinventions, so they can correct the mistakes and avoid the prejudices of the original works.