Explain why you'd choose to replace a female Marvel character's existing backstory with the backstory of the male version of that character instead of going with the Marvel existing version of that backstory for that character. I'd like to hear why you find that to be a compelling practice, and why you think that's a good idea in the context of an accusation of something being "sexist weak-sauce."
My answer? I think diverse representation matters more than fidelity to unimportant elements of source material.
The MCU leads have been more white, male, and American than the per capita rate of that group among the human race. Yeah, the films are adaptations of comics that were often made by white dudes from New York, but the narrative resonance of the characters' struggles is, most of the time, not really linked to their sex, race, or nation of origin.
Doctor Strange could have been British. His defining character trait is hubris and perfectionism.
Reed Richards could be Chilean.
Hawkeye could have been any race or sex, because as far as the MCU is concerned, his defining traits are that he's humble and good at connecting with normal people while working on a team full of demigods.
Now, Captain America being a reflection of America, trying to be an earnest representation of its stated values while being dubious of all the ways our leadership has been hypocritical? Having that be a white man is meaningful, because when Steve puts principles over 'playing by the rules,' he holds a mirror up to a LOT of white male Americans who could benefit from a lesson about respecting those who have less power than you and helping them become strong too.
And Tony as a repentant part of the military industrial complex? Again, solid white dude material.
Natasha's film interrogated how society objectifies women and tries to take away their free will and control their bodies. You could do a similar story that looks at comparable patterns involving toxic masculinity, but the patterns of control would be different. Natasha
could have been non-white, but you gain a bit by couching her origin in a nation often portrayed as hostile, to fit in with Cap as a person who cares more about doing the right thing than about tribal loyalty.
I never watched the MCU Hulk movie, so I don't know whether it delved into how society can teach men to respond with anger. Theoretically you could have told that story with a Banner who isn't white, which honestly might have been interesting to examine how society responds differently to the emotions of black men versus white men.
Later on, Peter Quill is a kid stolen away who misses Earth and makes its pop culture his identity, but he has empathy for other people who have lost their homes and families. That could fit pretty much any race or sex. I mean, a person of either sex can attempt pelvic sorcery.
Spidey doesn't need to be a white guy. That said, when they made a non-white Spidey, his specific ethnic origin and the expectations placed on him because of it help motivate his character. I've enjoyed all the Spidey movies well enough, but Into the Spider-Verse absolutely was the most compelling, because the character had the most going on.
Anyway, I'm rambling.
They're making a film series that will be viewed by people around the world. Half of them are women. If you can get the same emotional resonance out of a character's narrative
and provide more representation to appeal to a broader audience, I think that's good business sense, not to mention just ethically decent.