I'm okay with it. Personally, why not make all the game cases black? I'm not a big fan of the white Wii game cases. In the end though it doesn't really matter to me one way or the other.
Although, if they wanted to make the game stand out, black is probably the worst choice for that. Ninjas and assassins wear black specifically because it DOESN'T stand out. If they want to stand out it should be like neon orange or something, like they use for prison jumpsuits.