Crowley and Aziraphale didn't kill anyone. Michael destroyed the universe. Yes. But.
If they let Adam destroy the world in S1 or their superiors to start a war, it would not have been them doing it either. But it would be a weird conclusion to a story about a bunch of characters who try to save the world to - not save it.
What some of us (everyone did before S3, surely?) expected was that they will save the humanity they had lived among. Not die and hope god, who is a cruel heartless mean asshole, will start a new one like they asked. I see no point in this. I see no reason I should believe it. I would never have chosen for a God to start a new universe. In my fantasy show that is satire on religion. It would have been 'better' if they killed/eliminated God and disappeared because of that and from their death/decision/sacrifice the new universe started.
But I still would not like it. There could be a multiverse of other universes where someone with my face lives in each one and good for them I guess, I hope they are happy, but it makes no difference to me.
Just the same as it makes no difference to me that people have a million other beliefs about what is happening after we die or outside of what we know.
Jesus deserved explanations. Adam deserved to live the life he chose. Anathema and Newt deserved a long life after their bravery. Madame Tracy deserved a long retirement. The Them deserved adulthood they fought for.
Aziraphale and Crowley deserved to breathe and be safe and tell each other everything they never could and deserved the longest hug in the existence of anything and they deserved a quiet cottage with nightingales and a future full of bickering and exchange the softest, sweetest glances that turn water into syrup.
Angels and demons deserved to be free from their shackles and go off to do whatever they wanted in the vast universe.
Nina and Maggie deserved happiness in wherever they were off to. Mr Brown deserved luck in his next adventure. And Mrs Sandwich deserved to be told that the angel she berated saved her from eternal flames.
All the kids and animals and plants deserved to keep on living in their universe. They did not deserve to be wiped by flood because someone didn't like them. It does not matter that new ones were brought in. It does not make it a good ending to me.
The charm and beauty of Good Omens was the commentary of how even two supernatural powerful beings can't do much about any large events but we watch them choosing the right thing where they can.
And then they stumble on the Big One and make the right decisions. Because they have hearts in right places.
I can't stop big oil or armies, I can't build a house for everyone, but even if never perfect, I can and should and will - try and do small things where I can. Because - you never know how big a difference it makes to someone. That's the message. Fight for the world we have, now.
That's what I expected to see in the Finale.
I wrote this as a comment on someone's post but decided not to post it to them directly.