I'm usually all for showing racial diversity. However, in this case, I think it's a mistake to base this statue on an image that everyone recognizes, but then alter it to appease racial sensibilities. I also find it disingenuous, because it's long been a fact that the NY Fire Department is almost all white.
Personally, I think such memorials should be minimalist or abstract, and not realistic figurative images to avoid these issues. There was an interesting article about this in the NY Times a few days ago.
Anyway, the question is moot; they've cancelled that version of the statue.
