I'm going through some of my trawls, and I'm reading the early Gazetteer product by the Paizo crew, almost of all which was incorporated whole cloth into the Pathfinder Chronicles Campaign Setting... I believe. Anyway, the largest section of this is the "Nations" section, and I thought I'd add my comments as I read it, since it's a slowish Saturday afternoon for me.

Absalom: I'm currently reading the Old Testament on audiobook while commuting in the morning, and it wasn't that long ago that I finished the two books of Kings and started well into Chronicles. The name feels fake to me, knowing of course, that this is King David's son who led an ultimately unsuccessful coup against the King. I know that America has largely lost many of the details of its originally Christian cultural traditions, and people don't recognize Old Testament stories the way that they used to a few generations ago, but it's still weird that they use such a clearly prominent Bible name. Other than that, though, I don't really have any problems with this element of the setting. I think the siege castles of weird dungeons just outside of town is a stupid D&D affectation, but that's easier to just ignore than to overtly change it.
Andoran: The self-righteous proselytizing of "muh democracy" was tiresome before I even finished reading the basic description. Sadly, his over-the-top stupid detail tends to hide the fact that otherwise Andoran, as a nation with cultural and ethnic ties to both Taldor and Cheliax, but unwilling to accept the rule of the House of Thrune, is a fine idea. I don't have any interest in that non-stop ideological bent of Andoran; that needs to be replaced with them just acting like normal people, not woke mutants. But I do like the idea that in spite of their ties to both Cheliax and Taldor, they're unwilling to unite with either until they get their act together. But maybe they're more like the Commonwealth than like the fully independent US, i.e., all of the former Taldoran and Chelaxian nations still recognize the authority of the thrones in Oppara and maybe even Egorian; they simply can't work them them. For that matter, other former dependencies like Galt, etc. will have this same thing going on. I don't know if it's because Paizo is made up of professional woke mutants or not, but they don't understand how normal people think and act, and have made some of the "personalities" of some nations unbelievably one-dimensionsal and tedious and frankly unbelievable.
Belkzen: In one ironic place where I actually agree with the woke mutants in gaming, I think orcs as they've been portrayed in D&D and RPGs in general is pretty boring. This doesn't have to have anything to do with the "orcs as black people" nonsense; all the way back to early Warhammer, Warcraft and Heroes of Might and Magic games in the 90s, the idea of orcs as at least somewhat sympathetic if savage and barbaric peoples who act more or less like people rather than caricatures has been growing. Before getting coopted by the woke mutants and leading to the nonsense of 5.5's "Mexican orcs" joke. Anyway, I've already talked at length about how to make orcs more interesting, and I've done this already in Old Night; I'll no doubt do the exact same to Belkzen. Having Belkzen simply be "Mordor, but without a real Dark Lord holding it together" was never very interesting to me.
Brevoy: This is a weird frontier region that because it is largely disconnected from most of the rest of what's going on in Avistan, doesn't really need anything changed.
Cheliax: Other than downplaying the open-ness of House Thrune's diabolical connections, I probably don't need to change much here either. I think it's ridiculous that a whole society of open devil-worshippers would put on a civilized face, so we'll have it be more a case of Gothic aesthetic and secret, or at least discrete with plausible deniability connections to devils. I also dislike the myriad of distinctions between fiends in D&D and D&D-like games. Sure, sure; factions that don't get along with each other, that makes sense. The full on use of alignment to separate them along the chaos/law axis doesn't. That probably doesn't matter too much to Cheliax's nature, however.
I also want to make Cheliax to still be (at least on paper) suzerain over places like Andoran, Galt, etc., although the strength of that suzerainty is waning fast.
Druma: The idea of a nation of capitalist-cultists with a religion of consumerism is exactly the kind of nonsense you'd expect from Seattle weirdos. That doesn't mean that the idea of a mercantile kingdom with a weird, clannish aristocracy isn't salvageable, though, just that you need to downplay the over-the-top weirdness that Paizo allowed Druma to accumulate.
Galt: The idea of a French Revolution that's been going on for generations now is also stupid. Like with Andoran, Galt needs to tone down it's over-reliance on one, kind of overplayed and shrill idea. Sure, sure, it's unhappy with House Thrune, and the degree to which its leaders actually still support being considered a part of Cheliax, when they're quite a ways away from it anyway, is OK. The idea that there is a competing faction of nouveux aristocrats, and skullduggery and intrigue, murder and political machination is commonplace in Galt; I can get behind all of that. But people still need to actually live normal lives, or this kind of thing can't last. The real French Revolution didn't last 40+ years; it lasted ten and for decently long stretches there, it was quiet, only flaring up into widespread violence on relatively few occasions.
Geb: I don't know for sure what to think of the high-magic countries like Geb or Nex. I understand why they exist, I suppose, but I've never had much use for them. I think Geb also feels like a less-developed also-ran of Ustalav. To be fair, I haven't read the Blood Lords adventure path. I'll probably uneasily leave it more or less as it is, but of course, since I greatly prefer a much more low level and low magic game, I'm not quite sure what an African or semi-Egyptian undead nation will actually offer me. I'll probably mostly just refer to it, if at all, very obliquely and otherwise pretend that it doesn't exist. honestly.
Irrisen: I'm not quite sure what to make of this one either. A nation where it's literally always winter is a wasteland, not capable of supporting a population. One ruled by fey-touched witches and whatnot, where winter is long and cold and the witches have a cold-weather Frozen kind of aesthetic works, but again, it's too exaggerated to take seriously. And the adventure path set here literally has an adventure where you're supposed to travel to WWI era Russia and deal with Rasputin. Lolwut? I need to do a bit more research into the details to understand exactly how to change this, but right away, I know for sure that having it literally always be winter doesn't work.
Isger: The notion of Isger as a thoroughly dominated frontier region of Cheliax, recovering from a devastating series of invasions by goblinoids (or orcs) and now a kind of Mad Max-like shell of its former self probably doesn't really need any particular change at a high level. Details may, of course, vary, but the Gazetteer doesn't provide many, and I don't think I've read any modules or anything else that takes place in Isger that I'd feel inclined to change.
Jalmeray: This is another high magic bastion of wokified Orientalism. I've met way too many Indians to be impressed with Indian-inspired cultural elements in gaming. But as a foreign place with an elemental/genie kind of vibe that you don't actually do much of anything with, I suppose it works. Maybe the Princes of the Apocalypse can actually be from a place like this, or at least are worshipped here. A cult of "elemental evil" reigning on Jalmeray is more interesting to me than a culture of Bollywood martial artists.
Katapesh: I've always quite liked Katapesh more or less as it is. Or at least as it was in 1e. I hear that they've taken the tooth out of it, like so many other elements, in the wake of the move to 2e, so I'll almost certainly be ignoring that. The chance that I actually get to doing anything meaningful with 2e or its products is pretty low, though, so eh. Who cares?
Kyonin: While I admit to not being a huge fan of fantasy elves and weird, flaky elf-kingdoms, I also recognize that it's probably important that they exist in a D&D-adjacent fantasy. I wonder sometimes if I should swap the elves for some kind of fey-touched humanoid that's a little less... elfin, or whatever, (even if they use the same name) but I'll otherwise probably pretty much ignore them.
Lastwall: While the concept of Lastwall is fine, actually finding something interesting to do with it seems kind of a lost cause. In 2e, Lastwall has fallen and been converted to the Gravelands. I might go ahead and do the same, honestly, in one anachronistic referral to 2e. At least the Gravelands as a place for adventure is an interesting place to go. Lastwall was just like hanging out on a self-righteous military base, and then going somewhere else to actually do anything.
The other alternative is to give them the melancholy aspect of the fading Crusader States; aristocrats, formerly warriors, surrounded by foreigners and holding on to a way of life that is doomed to end within a generation or two. But that makes Lastwall more like a normal place, with Ustalavian commoners running an Ustalavian way of life outside of the ethnic and cultural Taldoran nobles castles. It probably doesn't matter. Paizo couldn't ever figure out anything interesting to do with Lastwall other than destroy it, so maybe I just ignore it too. That's the benefit of a large, diverse setting like Golarion. Anything that I can't think of to make actually better than what they came up with, I can simply ignore and pretend like it doesn't exist at all. I kind of like the idea of it being like a portion of Ustalav, except under the influence of foreigner-kings who owe no loyalty to Ustalav.
Or, if not Ustalav, maybe Molthune and Nimrathis, etc. from the south.
Linnorm Kings Lands: I changed the name slightly to make it fit alphabetically; in the Gazetteer, it was referred to as Linnorm Kings, Lands of, which I thought was kind of dumb. This nation is more or less OK as is. I'd, again, tone down it's "wintriness"; Scandinavia is certainly a habitable place today, for instance. And White Astrid the female Linnorm King is pandering to people who apparently don't know any real women. But those are minor details; mostly a kingdom of para-Vikings tends to work fairly well in most Eurocentric fantasy.
Mammoth Lords Realm: Another one with the strange alphabeticization; but still. A place where Conan-like barbarians live alongside Rancholabrean fauna and even dinosaurs coming up from a Pellucidar-like Underdark vault deep under the earth is fine.
Mendev: This is another nation that has one, too-shrill note for its existence. I think treating it like it was before the Crusades, i.e., kind of like Brevoy, but with lots of companies of mercenaries due to conflicts with both Brevoy, Numenaria and Sarkoris/the Worldwound is more interesting than literally a nation of cold Crusaders and various pointedly corrupt hangers-on.
Molthune: Like many of the former Chelaxian or Taldoran colonies, I prefer to see Molthune as simply a more autonomous frontier region of Cheliax still; one that is not subservient, and might even be openly rebellious against House Thrune, but not against the notion of a united Cheliax of which it is a part. Othewise, surprisingly little else needs to change. The same can be said for Nimrathas, except their conflict and rebellion is more local.
Mwangi Expanse: I actually like the idea of savage pulp-tale inspired jungles, and Paizo have only somewhat poisoned this idea with their leftist disapproval of "colonialism" and "racism." Still, other than ignoring those themes, and maybe race or alignment swapping a few details here and there, this works pretty well as is.
Nex: I'll be honest with you; I know even less what to do with this kingdom than I do with Geb. I think maybe the two of them work better if, instead of being high fantasy magical superhero countries in two flavors, they are instead shown as a post-apocalyptic wasteland (in two flavors) based on based battles of two Heresiarchs or other powerful mages that are more like The Ten Who Were Taken rather than D&D archmages. But I just fundamentally don't really like or trust the high magic stuff, so where Golarion focuses on that, which it should as a setting meant to have something for everyone, no doubt, I will tend to either change the theme or just ignore that area altogether.
Nidal: This is another place that I'm not quite sure what to do with, and neither is Paizo, I feel. The idea of a place under the thrall of the Plane of Shadow as it's theme is fine, but in doing that, they've created a land where agents of Nidal operating outside its borders is much more interesting than anything you could actually do in Nidal itself. I'd probably have to have it be an area that's "coterminous" for lack of a better word with the Plane of Shadow and replace its capital that you're never supposed to visit anyway, with something like Gloomwrought from the 4e Shadowfell book would work better.
Nirmathas: I prefer to see this as a rebellious area of Molthune, and therefore, like Molthune, a frontier province of Cheliax. Closely allied with whatever Lastwall is, and actually the subject of plenty of sympathy from day-to-day Molthunian people, it's more a case of the terrible leadership and mismanagement of Molthune by its elites that has led to the crisis that it finds itself in. Nirmathas also doesn't see itself as anti-Chelaxian, and has in fact made some tentative overtures to Cheliax for aid against the mismanagement of those of Molthune, but Cheliax has its own problems, is in decline, and the House of Thrune doesn't care much about the plight of a bunch of frontier yokels and their claims of being oppressed by bad nobles.
Numeria: I've never really cared for the idea of a "Barrier Peaks" kingdom, which is honestly exactly what Numeria was meant to be. I'd rather see it as a semi-barbaric land, but instead of aliens and robots and lasers, I'd be more likely to have Lovecraftian entities that also share some similarities with the gray alien mythos adapted to fantasy be the source of the weirdness. If I ever were to get around to adapting the Iron Gods adventure path, it'll be a real challenge given the significant changes to the base setting.
Osirion: Your fantasy needs an Egypt. There's nothing significant I'd change about this one.
Qadira: I don't know why Qadira has to be merely the westernmost province of an unseen and undescribed vast Keleshite empire. I mean, I guess they were going for the Imperial Persian feel here, but Qadira vs Taldor already gives us an effective Sassanids vs Byzantines vibe without needing to postulate a completely unseen eastern majority to Qadira. Let Qadira just stand alone. And with that minor change, I don't think I need to do much else. I don't particularly like Sarenrae as the patron goddess of Qadira, but I'll change all of the religion of my Golarion Remixed anyway, so I'll deal with that in another post some other time.
Rahadoum: This is another one of the stupidest idea of the Golarion design team; a kind of western north African kingdom that is defined by being aggressively anti-religious? Yeah, no, that's dumb. I'd rather combine Rahadoum and maybe even Thuvia as merely regions in a Barbary Coast like situation. And the Rahadoumi (?) are no more or less religious than anyone else. What an inane idea.
Razmiran: Whenever Paizo attempts to do something weird with religion, it's a mis-step. I don't mind a tyrannical wizard-king as a ruler, but him having this secret cult where he pretends to be a god and isn't is just silly. Again, I don't know how much changing that matters; I don't think there are a lot of adventures or other material that really focuses on the Razmiran cult that I'd have to even change anyway.
River Kingdoms: This feels a little too patchwork for my taste, but I'll probably leave it more or less as is. I haven't ever read the Kingmaker adventure path, so until I do, I'm reluctant to postulate any significant changes until I do, I suppose. I'm more likely to see the River Kingdoms as the River Communities, however, and see them as a decentralized yet culturally contiguous area less marked by constant warfare against each other and more marked by threats from their neighbors encroaching on the border communities. Paizo already does this part OK, so it's just a question of focusing more on that instead of violence just being something that's always happening between different sections of this area.
Sargava: Sargava is a metaphor or allegory for how bad European colonialism is. Since I tend to think European colonialism is mostly good for the natives, if not necessarily for the Europeans, this is actually backwards; the failing of the Sargavan colony due to being cut off isn't something to be celebrated and accelerated, it's to be mourned. It's a tragedy of the greatest order. I'll tend to focus less on the failing of Sargava, though, and make it probably more thriving.
Shackles: The Shackles was such a disappointment. Paizo couldn't think of what to do with a pirate-themed area other than make it a collage of all kinds of other crap that doesn't fit. It really just needs to be northern, mostly Chelaxian, pirate-lords on a kind of Corsair Coast. Hey, have I had that idea somewhere already before? If I want to have a darker version or element within it, than something like Iron Kingdom's Cryx works well. Otherwise, yeah; just borrow loads of Freeport-ish stuff and make it just piratey. The Shackles was hugely, hugely disappointing to me. I looked up my original review when I first got it, and at the time I was bravely trying to like it, it seems, but now I just find it pretty silly and unlikely to work for me.
Sodden Lands: There isn't much material, I don't think, set in the Sodden Lands, but a place lashed by a supernatural storm that won't abate after decades, inhabited by 1) savage cannibals who attack and eat anyone who lands on sight, and 2) an abandoned soothsayer culture who's soothsayers saw something that caused them all to commit suicide; I mean, what's not to love there?
Taldor: As one of the biggest, most consequential, but still kind of tragic nations of the setting, Taldor works pretty much as is. It's basically the fantasy version of the late Byzantine Empire, but you have the opportunity to reverse the decline rather than watch it disappear and get swallowed up by the Ottomans and the Islamic conquest, if you like. Not that Paizo's woke mutants would ever really understand that theme exactly, but I do. I'd have to adapt War for the Crown, if I ever do, to make sure that I focus on that theme rather than sexism or whatever stupid theme the authors gave it.
Thuvia: Another nation that is based on a trumped idea that isn't deep or interesting enough to support a whole nation. I'll just merge it with my revised Rahadoum. Maybe the sun orchid elixir can still exist, but it's just a significant trade good, not the whole raison d'etre for the whole nation.
Ustalav: This was already always one of the best elements of the Golarion setting. Although I've heavily modified it into my Timischburg nation for my setting, if running a Golarion Remixed, I'd change very little if anything of this, other than perhaps to expand its borders a bit into the dubious neighboring kingdoms that I don't particularly care for.
Varisia: Varisia is another one that I quite like as is, at least if I'm specifically playing a Golarion Remixed game (although once again, my Humberland/Hill Country region largely can be seen as a reflection of the same themes.) The only thing I'd change is replace Kaer Maga with some other city that isn't so stupid. I'm considering the old 3e Bluffside, but I still have to read that book to verify it.
World-wound: I actually like the idea of Old Sarkoris better than the World-wound. I land of creepy witches and barbarians? Fallen to demonic or Lovecraftian cults, but still there, just a place that's almost as bad as "an Abyssal layer, but on the regular world." Sure, sure, they summon all kinds of obyrith and aberrration like insanity, but it isn't literally the Abyss spreading across the landscape. It's still a normal place, more like the benighted and creepy backwoods of Lovecraft's stories like Innsmouth or Dunwich.
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Anyway, that's my review of the nations of the Gazetteer, at least. The next chapter is on religion in the Inner Sea region, but I already have my alternate D&D pantheon. Curiously, I detailed it in a post in which I was also talking about Golarion Remixed.