I've actually given a fair amount of thought to this issue

I'm glad I'm not the only one. I hope you like S8!

Possibly long-term angst.

I think for me that would be almost as bad as flat-out annihilation b/c, well, I'm tired of S/B angst. They had reached such a good place in S7 that realistically they should be making progress, not taking two steps back again. And with annihilation I could say "Screw you, Joss" and stop caring, but with angst, I'd probably keep coming back for more in the hope of resolution, despite knowing better.