I don't understand your point. The internet went nuts just off seeing Thanos despite the fact it was this guy playing him:
Who is that? You have no idea, do you?
They care about the character, not who is playing him. And I use the term "playing him" loosely, because Thanos (and most likely Apocalypse) won't be some in depth mo-cap session like Smaug or Caesar, nor will it be their voice. If nobody told you it was Josh Brolin playing Thanos in this scene, you'd never know:
And nobody would give a fukk who it was, either. It's Thanos, that's all they need to know.
Fred.