The content of Nick Fury's character is the same regardless of his complexion
Culture does affect a person, though; if that were untrue, then black comedians would meet silence in response to their impersonations of how white people act. Instead, we all laugh because we know there is a difference and the exaggeration of that difference is good for a laugh.
if we were all so interchangeable that we need only put on make-up to be a new race, then we truly would lose our character. Our differences should be celebrated and not homogenized.
That said, the black Nick Fury has shown me that Fury probably should have been black in the first place. It works; and the white Fury now comes across to me as the cheaper version. Of course, it doesn't help that I think about David Hasselhoff whenever I see white Fury.