Okay, honestly guys, after GI Joe: Retaliation where he played Roadblock, he's plenty black enough for me. There is a frustration, a tension, in the fact that he doesn't always play black characters, that he's got this sort of racial metamorph thing going on, which is cool for him, but discomforting for those who need to put people in boxes (like myself)... but after seeing him perform as an explicitly black character, knowing that he's willing and ready to represent that part of himself, I'm more than okay with him playing Luke Cage.
But more than that, as I think about him as Luke Cage, and how he made GI Joe 2 happen - The Rock is someone who can actually cause Luke Cage to happen. Otherwise... it probably won't actually happen. I know, I know Marvel said his name 2-5 years ago a couple times. But those are films that, like Ant-Man, like Dr. Strange, will only happen if someone outside of Marvel makes them happen. While I love Terry Crews, and think he'd be great in an ensemble, even a duo. When it comes to headlining a movie, carrying a movie on just one's personality and charm... Dwayne can actually do that, well. I can't think of any other strong black dudes who can. Can you?