On last night's Game of Thrones, the priestess Melisandre saunters in at the last possible minute to light up the Arakhs of the Dothraki in flames. It both offers the assembled forces of Winterfell and the audience at home a brief glimmer of hope before the next sixty or so minutes of horror film-meets-battle scene tension, and results in a clever cinematic trick. The swift extinguishing of that flame, like a city skyline experiencing a rolling blackout, telegraphs the pure carnage that awaits without zooming in on the details.
Narratively however, it also also literally represents the end of what was left of Daenerys' 100,000+ Dorthraki horde. Assumedly, sure, there's the woman and children and possibly a few rogue hoards of Dothraki still left in Essos, but lest the show pulls a trick of "Oh, we actually have some more Dothraki over here, you just couldn't see them! It was dark!" this may have been their sendoff on the show. It was an abrupt end to an entire group who we were introduced to in the very first episode, and a people we've spent more time with and understand better than many of the populations of the actual seven kingdoms (What, exactly, is even happening in, say, The Reach, lately?) And it points to a worrying problem.
Where once it seemed like Game of Thrones had something to say about the topic of immigration and the introduction of new populations to the staid old continent of Westeros, I'm no longer sure it's interested in such heady ideas anymore. It continues to burn up entire ethnicities like kindling in the fire of expensive battle scenes, revealing that it only introduced them in the first place to populate its numerous bloodbaths. Entire peoples with proud, interesting histories have been given the send off of a random red shirt cadet in Star Trek.
Game of Thrones first started teasing that it had something big to say about the human costs of the idea of boarders with the Wildlings, or as they preferred to be know, the Free Folk. The group was hated by many of those in Westeros simply because they had been hated for years. It was tradition. While, of course, we know now there was actually a very good reason why the wall had gone up in the first place, most of the characters in the show didn't believe that White Walkers and other assorted supernatural threats beyond the wall actually existed. Most of them had come to believe that wall was simply there to keep the Free Folk out. The show then spent several seasons humanizing the Free Folk, tracking the peace they eventually came to with the Northerners, and exposing centuries old bigotries as nonsense in the process. Indeed, some of the biggest, purest romantic storylines on the show were between Free Folk and Westeros citizens. It wasn't hard to see the show grappling with what Westeros would look like had it come to recognize the Free Folk as equals. An eighth kingdom perhaps? A spot on the small council? In some ways, the show might still attempt that, but it's not like it has that many Free Folk left to work with. Our only major named Free Folk that we know who are still alive are Tormund Giantsbane, Gilly, and baby Samwell. How much of the population is left beyond that is up for debate. Most of them have now been killed at least twice on the show, first by the White Walkers, and then as Wights.
Then there's the Unsullied. We're left to assume at least a good chunk of them have somehow survived The Long Knight, and will fight in the upcoming Last War, but it's not entirely clear if the show has any larger plan for them outside of "dudes who will die for Daenerys" (granted, that's about half of the show's cast at this point, but still).
Grey Worm is by far their most prominent member and should Daenerys sit on the throne, he and Missandei (another Essos-native, though the only Naath native featured on the show) could very well become a Westeros power couple. You have to figure Grey is on the shortlist for leader of the Queensguard, and Missandei as a candidate for a small council seat. Yet, should they survive, they've already decided they want to retire back to the beach of Missandei's native Naath. From a character perspective that's nice for them, but thematically, lest they change their minds, it means two of the most potentially powerful post-war characters have placed themselves outside of the answer of what would a Westeros with immigrants in place of power mean? Sure some of the Unsullied may survive the battle against Cersei and her rented Golden Army (yet another force of foreigners whose fate seems simply to die in battle), but as that population can't reproduce and form a lasting society in Westeros, there's certain themes their fate won't be able to directly address.
It's odd, because not only have so many outsiders died to protect the people of the Seven Kingdoms, but some the most prominent characters have foreigners to thank for the skills, experiences, and magic they've learned from both Essos and the Free Folk. So it sits a bit awkwardly that there's very few Free Folks or immigrants from Essos left to share in both the rewards and a slice of the power structure that emerges afterwards.
Sure, maybe given a few thousand more years, the White Walkers, had they survived, could have figure out how to man boats (or at least fly an ice dragon) over to Essos, but for the most part, so many people died for a threat their people didn't directly face.
This may also be a result of the show getting ahead of the books. Author George R. R. Martin has implicitly stated that ultimately he's more interested in exploring what the victors do with their power and responsibilities after they win a war than simply winning that war. It's easy to imagine that his future books may set themselves up better to imagine what a Free Folk run eight kingdom may look like, or what would happen if some Dothraki survived and decided they had every right to bring their wives and children over and set up a new home within the Seven Kingdoms. It makes sense that the HBO show killed off the Hoard because it made a great visual spectacle, but the literary version would find more satisfying material with the question of what would become of surviving Dothraki.
The show could still find some way to address these themes and questions that once seemed central to the themes of the show. Unfortunately, it's killed off so many immigrants and foreigners that it's left itself very little to work with.