Well, there's at least one person who won't be spamming your Twitter with Game of Thrones this summer: John Boyega.
The 25-year-old actor said,
There are no black people on Game of Thrones. You don't see one black person in Lord of the Rings. I ain't paying money to always see one type of person on-screen. Because you see different people from different backgrounds, different cultures, every day. Even if you're a racist, you have to live with that. We can ruffle up some feathers.
Now, before you Thronians get all up in arms, yes, there are two or three main black characters on Game of Thrones. Most notably there is Grey Worm, played by actor Jacob Anderson and Missandei, played by Nathalie Emmanuel.
But be honest with yourselves: Are these two really main characters? Do you know how many lines do they actually have?
So you can see Boyega's point. (And by the way, he's right about there not being any black people in Lord of the Rings.)
Back in 2014, A Song of Fire and Ice author George R.R. Martin defended the lack of diversity in his books via Livejournal comment:
Westeros around 300 AC is nowhere near as diverse as 21st century America, of course... but with that being said, I do have some 'characters of color' who will have somewhat larger roles in Winds of Winter. Admittedly, these are secondary and tertiary characters, though not without importance. Of course, I am talking about the books here, and you are talking about the show, which is a thing apart. I do think HBO and David and Dan are doing what they can to promote diversity as well, as witness the casting of Areo Hotah, which you mention. Of course, Hotah IS a guard... but he is also a viewpoint character in the novels, a brave and loyal warrior.
Areo Hotah is not specified as black in the books but is portrayed by actor DeObia Oparei in the show.
Of course, one could argue with George that there weren't exactly dragons and magical White Walkers in 300 AC. And also, oh yeah, Westeros isn't real.
Boyega, for his part, has become the face of a franchise that has certainly dealt with its own lack of diversity.
For years, Lando (played by Billy Dee Williams) was the only black character in Star Wars, a number that was raised to two when actor Samuel L. Jackson joined as Mace Windu. Neither were leading roles.
So, who knows. Maybe some day there will be a Game of Thrones reboot with John Boyega as Jamie Lannister.