Veltharis ap Rylix
Legend
Let me rephrase: I think there's a decent market for D&D to put out an East Asian inspired setting book, more in-depth than the micro-settings from Radiant Citadel.I don't think anyone was concerned that Sigil had a history of problematic content.
I think outside of aging Gen X and Baby Boomer players, there's probably a lot less enthusiasm for the old brand than the ENWorld population assumes. (See: all the threads on "hey, how come this art doesn't look like Larry Elmore stuff?")
The fact that Kara-Tur exists as the Forgotten Realms' East Asia analogue and they've continued to reference it as such periodically makes it a solid option for that, and the fact it has a history of problematic content and hasn't been meaningfully covered in 3/4 editions (multiple decades IRL and well over a century in universe) means that anyone who wants to learn more about Faerun's Far East have no option but to turn to that old, problematic content.
Which is precisely why I think a fresh, modern take on Kara-Tur could do well, if handled properly. Kara-Tur doesn't have to be D&D's big "fantasy East Asia" setting (I would certainly love to see more from the Radiant Citadel micro-settings) but it's still there as Faerun's Far East analogue, and it sticks out like a sore thumb to any Forgotten Realms fan who wants to incorporate some East Asian influence in their character/game.
If that's where people are going to look by default, why not give them a better version of the setting to look at?