I assume they're going to stick with European or anglophone countries for the foreseeable future - maybe with a few swings at
For as big a market (and place) as it is, they've kind of dodged the United States. You've got Unova, but that's before they really drew explicit inspiration from their locales, and you've got Alola, which is really its own thing culturally. Something like California, or Florida, or "the East Coast" in general would probably work.
Australia and New Zealand seems pretty much built for Pokemonization, so I'm not surprised they get so much play. Eastern Canada would work, too - Quebec and the Maritimes have a nice "shape" and a lot of usable cities.
Personally I'd be very into China, which could have a cool historical vibe. Same with Italy or Greece if you wanted to go back to Europe. Never considered India, but now that you mention it, lots to do with that as well... though a little trickier as their gods are still actively worshipped. No one's gonna complain about stuffing Zeus into a tiny ball, but you know they'd do a Ganesh and a Hanuman, and that might be a little tasteless.