I personally prefer Rokugan and Kamigawa to Kara-Tur. The fantastic storytelling in those settings are a bit richer since they aren't pasted onto Faerûn as an exotic destination for Forgotten Realms heroes to visit. Instead, they're stand-alone settings that are able to recycle Wuxia and Jidai Geki storytelling tropes in an internally consistent world.
Kamigawa is slightly preferable to Rokugan due to it's WotC ownership and the Planeswalker narrative hook to connect it with other D&D settings. The trade off there, of course, is that that invites players to make heroes of Ravnican or Therosian (or Faerûnian or Eberronic!) origin, who end up travelling to Kamigawa. And that ends us back in the Orientalist tourism/adventurism problem that Kara-Tur has.
In an ideal world, WotC would create a new setting from the ground up, crafted and created and written by Asian worldbuilders, and approved by Asian markets for sale. It doesn't have to be true to any one country's mythology or folklore, but it shouldn't be a pastiche of caricatures of various stand-in cultures (mainland empires based off China and India, island archipelagos based off Japan and Indonesia, etc). Ground up setting that is culturally sensitive and non-exploitative while allowing players to explore the storytelling tropes of Asian fiction, folklore, legend, and myth in the same way Forgotten Realms and Eberron explore the tropes of Europe and North American stories.
We've got most of the class builds needed. There are broad storytelling overlaps between chilvalric knights and old west cowboys and Japanese samurai, for example - it's why Kurosawa Akira's films were so readily adapted in the west into other settings (thinking Magnificent Seven and Star Wars, specifically), and why likewise Kurosawa was able to adapt Shakespeare onto Japanese feudal settings (Throne of Blood; Ran). But there are unique flavours and flourishes that are enjoyed by modern audiences around the world, including and especially in their source countries, and it's not a bad thing to want to tell those sorts of stories instead of or alongside Euro-American ones. Doing so just has to be in a respectful and collaborative way.
I don't think that precludes utilising an already-made setting like Kara-Tur, Kamigawa, or Rokugan, but it I think it's a lot more difficult when you're trying to reinvent settings created with a historic stink of orientalist appropriation and racist caricatures.
I know there ARE East Asian worldbuilders and publishers who have really cool settings out there. It might be easier to adopt one of those settings INTO official D&D, like they did with Mercer's Wildemount book. I'm sure Hasbro would prefer it be a setting that WotC owns entirely though, and Wildemount only exists because of the massive phenomenon that is Critical Role (Hasbro wanted in on the $$$, so WotC was able to coproduce the book). I do not know well enough the cost-benefit analysis for creating my above "ideal" framework, with all the market research and Eberron-style setting contest and hiring in appropriate staff, contractors, and cultural counsels, versus buying up the rights to an already created world and adopting it into D&D. Both could be very expensive versus the potential payoff.
I would imagine WotC would rather provide DMs and Players with the options they need (like the Samurai Fighter in Xanathar's or the Way of Shadow Monk in the PHB) and leave the world building to third parties to navigate between the scylla and carybdis in these perilous waters (negative public opinion and $ value loss).
If they CAN create or promote such a setting, however, it COULD align with Hasbro's goal of creating marketable worlds to play in that can eventually be films that aren't absolute rubbish like Book of Vile Darkness. I know that's a big part of why they hadn't given up on D&D in general after 4e. 5e has paid off very much so, but it's still a bit player in a bigger portfolio, and any new setting has to align with their market goals, among them: synergy with other Hasbro products like MtG; tapping into adjacent popular fandoms such as Critical Role, Acquisitions Inc., Rick & Morty, & Stranger Things; or building up & supporting a core setting audience already well-known in D&D (FR, Eberron, Planescape, Dark Sun) for the purpose of synergy with video games, movies, and other media products & paraphinelia.
East Asia is not as tapped a market as Hasbro would like for D&D. There's a lot of room for expansion of the fandom in Japan and South Korea, and potentially huge expansion in China if they can tap into that market. Such a setting, if done right, could be a lure for new audiences. Wuxia and Chinese mythological settings (Jiānghú) and Japanese period dramas (Jidai geki) are featuring a great resurgence these past years in both live action series & movies and in animation.
Furthermore, the most popular trope in Japanese anime right now is the Another World Setting (Isekai). A new D&D setting connected to our world like Forgotten Realms originally was (or say, Dungeons & Dragons the cartoon), but pulling ordinary people over the threshold into the fantastical might be perfect market coordination. Granted, Isekai settings TEND to be western-inspired fantasy world, but they aren't always as such - some of the most prominent ones that come to my nostalgic mind are InuYasha, Vision of Escaflowne, Fushigi Yugi, and the Twelve Kingdoms. I know those are all older worlds, but they are models for what I'd particularly look for in an Asian-inspired D&D setting. I'd also look to Netflix and the countless mythology-inspired C-drama, J-drama, and K-dramas that have been recommended…
