When making a story about one of these Urban-Fantasy-Style "this World looks exactly like ours on the surface but there is a Secret Hidden Fantasy World", sometimes the goal of the concept is to help the audience imagine the whimsy of the setting in their real world… Giving them not just the fantasy that fairies or dragons can exist, but letting them indulge in the fantasy that fairies and dragons can exist right under their noses, in their apartment complex, in the grocery store, in the communal garden they pass by on the way to work...
Sometimes the goal is to use these Fantasy Elements as metaphors that reflect and critique the real-life problems in our real-life world. Yeah, Dragons secretly exist, but these Dragons are also clearly a metaphor to predatory capitalist business practices or something, and that's Bad. It also allows you to think of this world as your own, as a way of making you think of the parallels between that world's supernatural troubles and your mundane ones. But I think a lot of stories end up as a mixture of the two, a balance between the dream that allows you to roleplay that maybe Magic is real, even as an adult, and being a thoughtful fantastical metaphorical frame for real-life problems at the same time. Maybe the Dragons are Capitalism, but at least them being Dragons is still Objectively Cool and maybe it's kinda funny to imagine you are secretly working for one of them too, or imagine how the fairies secretly protect you from their machinations.
'Good Omens' has always been in that third category, right from the original book. Heaven and Hell are metaphors for real-life harmful power-structures, in the book it's the Cold War Era Global Superpowers, the show alternates between that original concept and them being a metaphor to gigantic mega-corporations. It is Bad that they exist and meddle (or try to meddle) in Human affairs in the name of their mutual beef with each other. They are clearly, explicitly harmful to humanity as a whole because they are a stand-in for real-life things that are harmful to humanity as a whole.
But… it's also fun to imagine that Angels and Demons could be walking among us in our world, and 'Good Omens' clearly knew it. Like, the whole premise of Crowley's initial characterization is both a satire on the concept of blaming Humanity's evil on Demonic Influence (THIS shit is not his fault! Or any other Demon for that matter! Only Humans can think up these things themselves!) and a sort of invitation for the readers, to imagine whatever silly minor annoyance kinda ruined their day is the work of this lovable Demon.
It was a running joke in the Fandom for years for a reason, it's fun to imagine that whatever stupid little annoyance happened to you was because of a cool-but-silly little Demon who's just doing his job, even if his 'job' is also Metaphorical Cosmic Imperialism. It's clearly fun, and it was written in the book to be a Fun Concept.
Same thing with Aziraphale and his Bookshop. The whole joke there is that used bookshops which are actually clearly just the owner's excuse to have extra-storage space for their book collection and they have little intention to allow you to actually buy anything and makes you wonder how they stay in business actually are actually absolutely a thing that exists in Real Life!
Why are they Like That? Where do they get their money if they clearly want to sell as few books as possible? Maybe this is all a front for a supernatural immortal bibliophile? That's also fun to imagine.
There's a lot of other little touches like that in the book. Hey, have you ever noticed that every car always seem to have a 'Best of Queen' Cassette in it even if you don't remember buying one? Yeah, the cassettes just transform into them, that's just a commonplace supernatural phenomena, everybody knows that. Yeah, obviously there's no 'Prophecy' in the world that's entirely accurate… because the one 100% accurate prophetess in the world made sure her Book of Prophecy ended up only with her family. Even the fact that the world ended up completely restored and a lot of characters ended up with only hazy memories of what happened and most of humanity decided to ignore it and go about its business as normal… Maybe Armageddon did come in August 1990 but we were saved and everyone just moved on?
Every one of these kind of stories has to deal with the balancing act between the fantasy of Magic and taking the metaphorical real-life injustices the Magic is tied to seriously and literally. Or maybe it's less of a balancing act and more of a Yin-and-Yang thing, encouraging the audience to think of the little charming bits of Magic in their everyday life, also makes them acknowledge the parts that remind them of real-world harm.
As far as balancing all of this in Good Omens goes, the book makes Crowley and Aziraphale lovable but also makes it clear that they're not necessarily our heroes, the show chooses to make them our heroes but draws a firmer line between them and the system they were both complicit in and victimized by. Both Book Omens and GO1 are about how ultimately, these horrible systems' attempts to control those weaker than them and destroy the world will inevitably fail, and maybe if we put aside our differences, we could team up and get rid of them entirely.
And in the meantime, you can just imagine Aziraphale and Crowley are chatting up on their favorite bench in St. James Park or maybe they're going to your favorite local restaurant because they had to visit your hometown for a 'business trip'.
…But it does make sense that if you're going to do a story that continues from that point, that explores how Heaven and Hell, and the oppressive systems they represent, aren't going to be so easily defeated and they are still going to keep victimizing people and endangering the world - that you're to build up to a Happy Ending where Heaven and Hell are gone, completely. And while the whole 'Humanist Revolution' that has been set up seems like the most thematically-appropriate solution, it's a solution that pretty much has to always be in the future-tense. Again, part of the fantasy is imagining that the Good Omens setting could be our world, and if Humanity is going to wake up to the machinations of Heaven and Hell, put aside our differences and unite together to rise up against them and kill God ourselves… well, that would be pretty hard to imagine this is secretly the world we live in now...
There’s still a lot of different options with different pros and cons, different ways to execute them… Could you dismantle Heaven and Hell while keeping the Angels and Demons as individual life forms that were also victimized by the system? Could you turn all the Angels and Demons Humans and still keep up the illusion that this is our world even thought 20 million new humans suddenly materialized out of nowhere? Could you just trick Heaven and Hell into trying to control a random uninhibited planet for the lols?
But either way, I feel like Good Omens 3 just kinda chose the absolutely worse option? I want to say they ditched the whole delicate balancing act in favor of just treating every Magical element of the show as 100% part of the Metaphorical Oppressive System that therefor must be dismantled… but they didn’t even do a good job of handling that concept! Because, yes, Good Omens Viewers, at the same time they enjoyed the fantasy of living in a world where a Miracle from a mostly-benevolent Angel or a barley-wicked Demon could be just around the corner, did also engage with the aspect of the world that clearly metaphorically mirrored the hardships and oppressions of our world (as well as the clear indications that the literal hardships and oppressions of our world also exist in the Good Omens world).
The Good Omens world didn’t just feel like our world when it made for a pleasant daydream, but also when Crowley and Aziraphale were fighting to escape harmful systems that seem fundamentally inescapable, when the inability to heal from the trauma it left on them was hurting their relationship, when Adam fell into environmental-anxiety-fueled despair for the first time in his young life and his friends had to pull him out of it, when Maggie struggled to keep her family business afloat after the pandemic…
This world felt like ours both in the sense we were supposed to think all of this biblically literal stuff could be secretly happening in the background of our real life and in the sense that the supernatural troubles felt relatable and applicable to the problems we faced in our world. And instead of at least offering us a coherent empowering narrative about defeating these oppressive systems (even at the price of even the Fun Silly Fantasy Element) it just seemed to tell us that our world is doomed to die.
Eventually some powerful idiot is gonna snap and get their hands on the red button while everyone else is too incompetent or selfish or invested in their personal bullshit to stop them and the little people, the Humans, will have no agency to stop it at all and everything and everyone you know and love will die. And not only that, no one never had any hopes of saving the world or truly being free, because the Most Powerful Authority Figure around is just so powerful, there is no way to actually outplay Them. AND NOT ONLY THAT, these systems of oppression have been built so inherently into the foundations of the world, that there’s nothing and no one that could or should be restored from it. The only way to build something remotely better is to start over from scratch.
And the power to build back anything at all doesn't even come from Humanity! Or our protagonists! Or our protagonists' inherent humanity! They basically have to beg the Biggest Authority Figure around to dismantle/not bring back the system and then kill themselves and just trust said Authority Figure won't just break Their promise! There isn't really any good actionable narrative about how to dismantle a system or build things better to hang on to!
And after all of that, the ‘oh, no, THAT wasn’t actually our world! This new better world is ours! Doesn’t it just make you love our world so much knowing it’s so much better than the Good Omens world?’ shtick falls flat for many because the Good Omens world already felt like our world, because it seemed identical to it on the surface and it's fantasy elements were an obvious Metaphor for the troubles plaguing our real world. The same kind of troubles that the Finale spent like ~80 minutes telling us there's no real escape from and will ultimately doom us. And now we have to keep going through all of this without even the comfort of feeling like Humanity's Eternal Gay Uncles are boozing it up somewhere in the world.
