I personally think it isn’t wise to use an actor of any race in substitute of another, if that character’s race is part of the story. The only reason I could think of to change the character’s race, gender, status, etc. would perhaps be to tell a different story, but then it should be renamed and be a different story. But if a character’s race, gender, status, etc. is tied to that character’s story, then it shouldn’t be discarded frivolously.

From what I see, I feel that a lot of the disconnect is based on whether people find an attribute (in this case, race) important or not as part of the character’s story.