For non-iconic villains and support characters, go ahead. Big deal. The heroes themselves, nuh-uh (I consider Fury to be a support character, not hero).
Personally, I think the notion that Zarex mentioned that "minorities were considered to be outside of the mainstream in US society when many of our most popular superheroes were created" is a copout. I'm not jumping on Zarex personally; many people have said the same thing, he just brought it up here first. Yes, racial politics in media were a lot different back then. But even today, when most people are color blind, the vast majority of characters created for film, tv, and print are still white. And even when race issues in the media were at their most controversial, we still got great black characters - Black Panther (1966), Falcon (1969), Luke Cage (1972), Storm (1975).
If WB decided they were gonna reboot Harry Potter and cast a black child, the world would throw a fit, even though it was written at end of the 20th century. Why? Because everyone knows Harry Potter is a little white boy. If someone were to make Life of Pi, and use a white kid instead of Indian, people would also be up in arms. Because the kid in Life of Pi is supposed to be an Indian boy.
And isn't it kinda insulting to minorities to change well-known characters to a different race just to placate them? It's basically them saying, "We know there's black, latin, asian superheroes out there. But instead of simply including them, we're just gonna take this white character and make him black, latin, asian so you'll feel special." That's like putting a bunch of hockey players in blackface just to get black people interested in the sport.