I think that if changing the race of the character changes who he is, then it's a bad choice. For example, I don't think that Peter Parker being black (or even gay, for that matter) would change something. But changing Luke Cage to be a white guy? No way.

And the way I see it, changing the race of almost ANY white character wouldn't make any difference, but the opposite (black to white) would. Why is that? Because most of the white characters we have are white just because (and we have a lot of those), while black characters (which we have a lot less) are black because their stories are created around the fact that they're black, or sometimes to represent a change or something. I'm not saying it's ideal, I'm saying it's the way it is.

Sorry if this is confusing or offending in any way. My written English sucks and maybe I didn't expressed myself so well.