Still a detective story. And they already covered the detective aspects of Batman very well in the first two movies. You're picking at straws now, because there is a huge difference between the final installment of the Dark Knight Trilogy focusing on Bruce Wayne's reconciliation with Fox turning Johnny Storm black.
Im not doubting actor's ability to portray Johnny Storm's personality, but the fact of the matter is that Johnny Storm is white. You seem to have difficulty seeing that this is much more noticeable than a few inches on an actor.
Edit: How stupid would it be for Blade or Static Shock to be White?