gigoran is right.

i didnt have a problem with them making kingpin being played by the late michael clarke duncan coz even though he was not white like the comics, he had the size and acting ability to pull it off not to mention whether he was black or white didnt make any difference to the core of the movie.

see i also wouldnt have a problem if it didnt interfere with core relationships within the movie. but for F-sakes, they are blood brother and sister. not adopted or mixed race. so cut that bull out.

its just gonna be another super-hero movie with fantastic four slapped on. might as well call it kick-ass 3: the next generation and release it straight to dvd/Blu-ray.

Couldn't have said it better.

Black Panther has to be black. It's a huge part of his character history. Blade could be white, doesn't matter. Everybody wants to stick close to the source material? Okay. Then Sir Ian McKellen shouldn't have been Magneto. Scarlett Johansson shouldn't have been Black Widow. Robert Downey Jr. shouldn't have been Iron Man. Henry Cavill shouldn't have been Superman. Apparently though, only certain racial differences matter. So, Jews, Eastern Europeans, Italians, Irish, etc., all fall under 'white' and can play any 'white' character. Nobody is sticking to the source material. Nobody would have gotten upset if they cast some other white guy as Johnny Storm, even if he and Kate Mara (Sue Storm) had completely different ethnic backgrounds. But apparently the moment a black person is cast in a white role, everyone gets up in arms. In this version, the siblings will either be step siblings, adopted, or that off chance where siblings look nothing alike. But still, everyone is mad. The issue here isn't staying close to source, it's racism.