Uh, why?
Gender or race aren't really central to these characters so they could easily be changed without hurting the integrity of the stories. These characters are about their superpowers and often about their emotional trauma.
Changing their race or gender wouldn't really make a difference in any negative way but it would be more inclusive while at the same time being less boring and repetitive. Win/win situation, really. Especially if the want to play the whole reboot-game, too to sell the same product over and over.
Well, given the family history, I do think it's a no-brainer that Howard and Tony Stark should be white men. You don't become one of the government's largest contractors in WW2-era America if you're not.
Yeah, this is exactly what I was thinking. Howard Stark, at the very least, has to be a white man. It would make sense for Tony to also be a white man, but Tony could be a biracial woman. Of course, then they couldn't use the Black Sabbath song.
Here's a hypothetical - how would people have felt if J.J. Abrams had cast a woman as Captain Jane T. Kirk in the 2009 reboot?