Death Note is a story set in Japan, about a Japanese person, with deep roots in Japanese mythology and culture. By setting it in America, you are taking away much of the richness and symbolism behind the plot and the character's motives. Light Yagami is not white, he is Japanese, and so are a good portion of the rest of the characters. Casting Nat Wolff, a white actor, as Light Yagami was not necessary, and it detracts immensely from the story. It is no fault of the actor himself, but rather the fact that Warner Brothers studios cast a racially inaccurate actor.