Frankly, I think Game Freak should just toss out the practice of basing each entire region on real-world countries. Half the time they aren't even sticking to the culture they're basing themselves on anyway. See for instance: Japanese Oni as the legendary trio in the New York region? A desert with an underground Egyptian temple in the middle of Manhattan? Norse-inspired legendaries in the France region? Aliens taking over Hawaii? A monkey and a chameleon being starters in a region based on the UK?
Don't get me wrong, I think they're sometimes pulling it off pretty well. Alola generally has a nice Polynesian feel to it, Kalos has some nice French countryside, and some of the towns in Galar are decidedly British. But the nature of the games often demand that they insert biomes, cultural elements, or creatures in the region that have absolutely nothing to do with wherever they are basing the region on. I'd much rather see the region taking in real-world inspiration on a town-by-town level, which it already kinda does but kinda doesn't. Put in a big British city in the region, for instance, and revel in the British setting for that one city, but when they need to have a decidedly-not-English desert next door, with Malian architecture or something, they should stop pretending we're still in Britain. When they are putting in such specific references to places that clearly aren't the UK, it results in quite a mismash.
Take the town of Stow-on-Side in Galar, for instance. It's a dry, dusty mountain town perched on high cliffs, whose main attraction is the outdoor market where spices and tropical fruits are sold under the cover of parasols to shield the vendors and goods from the baking sun. I'm no UK native or expert, but it doesn't look like anything in Britain to me. Its architecture is reminiscent of a South American mountain town, if anything. So what is it doing in a region based on the UK? Or even, how is the region based on the UK when it has places like that in it? Heck, the name is very UK-like, it sounds like a cozy British town, but when a place is Somewhere-on-Side it explicitly means there's a river called Side running through it, and there clearly isn't. Stow-on-Side tacks a British name on a Peruvian village. It's as if the town was designed independently of the region it's in, and it's jarring. The places that look like they're in the UK work nicely with the narrative that says they're in the Poké-UK, but the places that look like they belong elsewhere kinda shatter the illusion - or makes me question why the narrative insists they're in the Poké-UK at all. Same goes for the decidedly Eastern dojo in the upcoming DLC. Again, it's fine that they have a dojo, but it doesn't seem to have anything to do with Poké-UK culture. By putting pagoda towers on the Isle of Armor, Game Freak has already given up on the UK setting, so why is it still going for that crown-and-armor theme?
My go-to game for examples of things done better than Pokémon, Breath of the Wild, pulls this off great. The desert town looks nothing like the volcano town, and neither look like the water town or the mountain town. They all do the things that feel natural for the environment they are in. That game's world has Aztec-style temple ruins in the jungle, Polynesian-style straw huts in the tropical beach town and small Swiss cottages in the freezing mountains, and it feels natural. This all works because they're not, for instance, framing Hyrule as Fantasy Mexico, even though there are locations reminiscent of Mexico in it. That would have clashed badly with the other elements which explicitly aren't Mexican. Granted, there's the caveat that different biomes are inhabited by different peoples, with their own cultures and their own architecture, but, well, that's not too different from the real world, is it? People in deserts have different ways of life than people in tall mountains, even within the same country. When gameplay considerations mandate that deserts are placed right next to tall mountains, in a region based on a country which doesn't have either, the cultural impact needs to be adapted likewise. And then it stops looking like the country they started out with, instead it starts looking like somewhere else entirely, and that's where it clashes for me.
So by basing their regions on single countries, Game Freak are setting up restrictions they can't even follow through with. Sure, they're getting very good vibes out of it for the locations that match the base country - again with the English or French countrysides of Galar and Kalos, the beaches of Alola, or the tall skyscrapers of Castelia City, but they step out of the boundaries when they add elements that have nothing to do with those countries. And that eager willingness to step out of the boundaries whenever necessary makes me question why the boundaries are meant to be there in the first place. Why pretend you're basing a region on New York when you add volcano caves and oni to it? Why pretend you're in the Britain, then add a town that would look more in place in Peru? Why have a sandy desert on a Hawaiian island? Such departures from the setting makes the setting feel half-baked. It's not the place it pretends to be, so why pretend it's that place at all? Can't they invent a Galarian culture and architecture from the ground up, instead of using British imagery as a crutch they're willing to toss away half the time anyway? Or, well, "toss away" is a stretch, they're merely replacing it with a Japanese or Peruvian or Egyptian or Mexican crutch ... you get the idea.
So yeah, for the next gen: Please, let us have a generic region. One that could be a little bit of anywhere, with design inspirations taken from various places when the need arises. Attaching the whole region to one real-world place gives too many restrictions, and when they are broken anyway it just feels jarring. Stick to the established restrictions, or cut them off entirely.