> having a globally shared buffer state, etc. is an anti-feature

Yeah, it feels a bit weird to not have some isolation.

Spacemacs offers layouts[^1] that give you some buffer-isolation. Each window has a "layout", and layouts have sets of buffers. It works well, but you can run into extra prompts if you open the same buffer from two layouts and try to kill it from one of them (kill the buffer (for all layouts)? just remove from this layout? In my mind the latter should just be the default).

[^1]: https://www.spacemacs.org/doc/DOCUMENTATION.html#layouts-and...