Turkey would be really cool actually. Plenty of diverse biomes: Flat steppe/grasslands in the center (maybe with nomads?) with a salt lake, sunny mediterranean shrublands dotted with ancient ruins in the west and south, mysterious hot desert stretching to the southeast, freezing snowy mountains in the east, cool rainy lush forests in the north (Safari Zone?), and a massive urban center in Istanbul in the northwest, presumably where the League would be. Throw in Cappadocia for a barren alien landscape in the center, pick and choose from plenty of rivers/lakes for swamplands/marshes, unlock Mount Ararat in the east and Hellespont/Troy in the west as legendary locations, place a hyperfuturistic rich oil city at the terminus of the desert routes to the southeast, etc. Putting the post-game Battle Frontier in Cyprus and adding an Aegean Islands exploration DLC to the west (a la FRLG Sevii Islands) would be funny. For Pokemon/story lore you can draw from Ancient Greek/Byzantine, Muslim/Arab/Persian and steppe Turko-Mongol lore (in addition to smaller cultures like Armenian, Georgian, Assyrian etc) and all of it fits. Too bad it won't happen due to obvious geopolitical reasons.Much earlier on someone talked about the Middle East/MENA not being a viable location because land, and thus Pokemon, diversity would be lacking but I've got to disagree there. Possible inspirations include -
Normal - Pretty easy to envision
Fire - Blistering suns, nomadic campfires, ifrit demons (great Dark/Ghost crosstyping potential)
Water - Oases, Gulfs
Grass - more shrubbery than trees, lean into grass-type livestock to reflect agriculture. Also plants signature exports like pistachios and coffee beans.
Electric - Not a lot, but there aren't really electric mice in the woods either (looking at you Pikachu)
Fighting - Nomadic warriors / more stuff pulled from lore
Ice - Deserts are notoriously cold overnight and there are actually famous ski resorts in places like Iran and Lebanon. It's not all deserts, they have mountains too.
Poison - We've dipped into scorpions already, but Muk 2.0 is right there with the oil fields
Ground - Desert. Done.
Flying - birds.
Psychic - Playing into seers, maybe stars of the desert sky
Bug - Scarabs basically have a mythology of their own
Rock - Mountains like everywhere else, but maybe with some mythological flair. Toss in some history with the Rosetta Stone.
Ghost - Every culture has ghost stories
Dragon - Middle East has traditional dragons of their own, but I'd love to see a new flavor come out based on the Chimera based out of Turkey and the Sphinx in Egypt.
Dark - Again, back to mythology
Steel - Damascus steel, scimitars, etc...
Fairy - aaaand mythology again
You've got desert climates, mountainous regions, metropolises, historical ruins in places like Persepolis and Petra, gulf and ocean access, and areas of lush, green growth alongside in-land rivers. You've got unique architectural styles, from millennia-old mosques and Chefchaouen, Morocco's Blue City to Dubai's artificial Palm Islands. Honestly, if you replaced Fortree city and the greenery of the hike through it from Mauville to Lilycove while also scaling down the grass and trees to shrubbery, you could easily place the Hoenn region in the Persian Gulf pretty effortlessly. I'd lowkey love to see that forest stretch switched with a semi-nomadic tribe (and gym leader) rotating through several sites (in a hypothetical reworking of Hoenn).