Having rewatched the finale, let me say: it hurts so much because they were so close.
Not just as in "Aziraphale and Crowley were close to happiness", but as in "they were so close to writing a good ending". There are so many interesting themes. Michael being tired of trying to make Heaven run smoothly when the men-shaped angels in charge are incompetent. Aziraphale forgiving Michael, which made me realize how crucial forgiveness is to him, and how it makes him different from other angels. Angels are not forgiven when they make mistakes. They are sent to hell or killed with hellfire. Forgiveness is not an angelic trait, it's an Aziraphale trait, because he truly believes that love and forgiveness can change things. And Aziraphale's struggle doesn't differ from Michael's all that much, because he too is tired from constantly trying and failing to do the right thing (they just have vastly different ideas of what the right thing is). These were all interesting themes that deserved an epilogue that wasn't "let's just get rid of both you and the system, to make a new version of you that is not traumatized any longer".
Crowley getting a confrontation with Satan was great actually. And I wish Aziraphale had gotten some closure with God as well, instead of being insulted and seeing his love be called predictable, messy and silly.
And as for their final decision, I still think it is stupid, but if they really really wanted to go that way they should have let Aziraphale and Crowley kiss. The scene just calls for it. When Aziraphale turns back to Crowley after managing to hide his pain (and how I loathe the fact that my angel died as he lived, repressing his feelings, without a real chance to ever speak freely about what he wants), it would have been so poetic if he just grabbed Crowley by the lapels of his jacket in one last, desperate kiss. Not to convince him to change his mind, but as a goodbye, as a "I'm with you, even in death".
They had the times and scenes to make this better, but for whatever reason (Neil Gaiman's writing? Prime's censoring something? I guess we'll never know) they didn't.
