I mean... the "new" Sultai culture is actually pretty realistic. Consider:
Khans of Tarkir Sultai: The Naga took control at some point in the past, and were running everything on brutal oppression and propaganda. The humans explicitly used ancestral necromancy in an attempt to keep in touch with a pre-Naga culture that wasn't shit.
Fate Reforged Sultai: We see the Sultai before the Naga took control. The Sultai ruling class started to make devil deals to stay in power, which lead to the weak little shithead Tasigur pissing off the Nagas (which probably lead to the Nagas taking over the clan in the Khans timeline, but lead to Silumgar taking them over instead in the Dragons timeline).
Dragons of Tarkir Sultai: We see the (former) Sultai as still being a predominantly human clan (like they were in Fate Reforged). There's still a bunch of brutal oppression and propaganda, but now it's done by dragons (Sarkhan says yay) and Rakshasa. As far as they're concerned, Tasigur being a weak little demon-pact-making jerk was directly what lead to their current oppression state (I wouldn't even be surprised if, over literally 1,000 years, the story mutated to "everything bad about our culture is a result of Tasigur being the worst").
The Sultai are probably the only clan that legitimately couldn't look like its original version in the new set, because Silumgar took over the role the Nagas played and "try to pick up where we left off" is going to look supremely unappetizing since it would involve making deals with the same demons that you literally just overthrew. But hey, "Sultai" is still going to be a compelling cultural identity to try to reclaim and build yourselves around, so...
(Outside of the game, it gives me decolonization vibes.)