Flame On

A black guy as The Human Torch in a new Fantastic Four movie?

Fine.

As long as Susan is black as well.

Because Susan Richards nee Storm is Johnny Storm's sister.

It would will be strange for her brother to be black and her white.  Kat Mara doesn't look like his sister.

It would also prove a large portion of the objectors correct that they changed the race of the character just for PC points and not a creative reason if they didn't change his sister's race as well.

The actor cast as Johhny Storm is out there saying that he's playing the part just to mess with the racists.  He's being a racist about it himself.  Shut up dancing monkey, shut up.

Messing with some parts of comic canon work.  Making Wolverine 6' 2" worked.  Moving Iron Man's origin story from Vietnam to Afghanistan worked.  Changing Galactus and The Silver Surfer didn't work.  Changing Dr Doom's origin didn't work.  Changing the background of Sandman didn't work.  Changing The Rhino didn't work.

Making Susan and Johnny storm different races when they're brother and sister in the comics... won't work.

Besides, PC people, if Reed Richards is still white you could have had an interracial marriage!  First one in a comic movie!