I cba with this narrative because they've casted a few black and asian people in Middle Earth, as long as they're decent actors it won't ruin anything for me. The Wheel of Time fan base had a portion who kicked off over that too and the actors were fine it was just a crap production that rewrote the books for TV. As long as the story and production quality is worth the money they've put into this and fits with what Peter Jackson established already then it will be great.
Someone here I think said they don't have the rights to the Simarillion so I'm not entirely sure exactly what this story is going to be if it's not actually something Tolkien wrote. After seeing the liberties taken and crap production value with Wheel of Time I am worried they could do the same here but I'm still optimistic until I see it.