I'm not against the idea of making literature and films break away from the white as a default race, all I'm saying is know your time period. England didn't have much of diversity pre 1700s besides a couple shades of white. When writing a story that takes place/is based in ye olden times Africa, you can hold off on the white people and have an all black cast. I haven't watched Fant4stic or AoS, but if you're making a story that takes place in a modern setting(aka Fant4stic/Agents of Shield), there's no excuse for not having a diverse cast.