I have to say this seems like splitting hairs.
This gets back to another this I've talked about wrt diversity in comics and movies, which is that while there's nothing wrong with white male heroes, it can be easier to identify with characters that more closely resemble one's own background. Indeed, there is another thread in the NGD right now about a Native American who as a boy was so annoyed that Thunderbird got killed off in the X-Men that he eventually created his own comic line. It's not current-Marvel's fault that so many of their characters hail from a point in the twentieth century where things were more white and male, and I recognize that while tweaking existing characters is hardly a perfect solution, at least they're making an effort.
I'd argue that the publishers' real problem is writing. I'd have less of a problem with a Chinese woman becoming Captain American than with the whole Hydra-sleeper-agent storyline. Because to me Cap's value system is more key to the character than his ethnicity or genitalia.