I actually don't see what he's got left to offer, tbh.
I feel the same about Lucifer. What will he do? Try to start the Apocalypse again? Been there, done that. Will he be a good guy then? I don't see it happening, especially if he made some sort of peace with God.
This.
Going into the episode I wasn't sure where they were going. The whole balance thing left me guessing til they finally planned it out. Sure it was an insane plan but I actually would have liked to have seen it. No light, no darkness. A new balance system for the universe.
I kinda thought that was a lazy explanation to be honest, just so that they find another reason to kill Amara if God would die. If they made the sun die without God, then I don't see how killing Amara would restore it since God was light and she was darkness. I mean the light would be gone anyways.
Castiel said he was ripped from his body, to an unknown destination or something like that. I thought he had been killed.
Still, whatever the unknown destination is, it's probably very bad for him, since Amara was retaliating after he'd literally stabbed her in the back.
The only thing that makes sense is for Lucifer to be an ally next season. I mean, he made up with God and teamed up with the Boys. I can see him being a Crowley type thing. Or maybe he'll be making a move for Hell again? Maybe he'll have a new vessel and will--I don't know.
There really is nothing for Lucifer to do unless he's returning to Heaven.
I was really surprised as I also thought Lucifer is dead! So I wonder what they will do with him, because the show doesn't seem to end anytime soon, so even if he isn't returning next season, at some point I'm sure he will. Heck I wouldn't be surprised if Leviathans come back too at some point, even if I don't want that at all!
The thing is, for Lucy to be an ally, you would need a powerful force/being to deal with. Look how many times they stripped Cas of his powers and toned him down! I truly can't imagine the boys having such a powerful ally, it would make things way too easy for them. Amara is on holiday with God, Leviathans were lame and I don't want a return, Death is dead, Michael could still be a potential villain, but I honestly think he's just damaged (I'm quite disappointed that God didn't rescued him and sent him back to Heaven, after all, he is his son!), so it's hard to imagine what Evil being could they come up with next that would require the boys to have an Archangel by their side.