|"..." - Black Bolt.|
This is a case where Marvel should go a different route. I think they should make him very alien in his look, like the Black Bolt of the Earth X Universe (pictured below), and make him a CG character that is motion captured by an actor of Andy Serkis' caliber, or even someone like insanely talented actor Doug Jones. Jones once said about working in heavy suits, prosthetics, and makeup, "I have to make that a part of my being and my physicality and again, acting is a full body experience and that's a part of it when you're doing a costumed character."
This is where Diesel has, so far, failed quite spectacularly. He has never shown the subtlety or nuance necessary for a role without speaking like this. Black Bolt is a role that absolutely requires a perfect capture of someone that can emote with only the most minute facial expressions and body language. It's a character we must believe can inspire his people just by being there and sending them a message with the merest nod. Diesel's ham-handed skills have never given the impression that he can handle such delicate work like this. Granted, I could be wrong, and Diesel may have gotten much, much better as an actor, but we'll have to wait and see.
Inhumans is slated for a July 12th, 2019 release.