> A single "closer" hot-key sounds very logical... Would it work for all enclosing symbols, even for | and " ?  How about something like CMD + Backspace (or CTRL + Backspace in Windows).

No.  Just the three paired ones.

> Picking just one of the closer brackets might be a bit confusing for closing " or | pairs...

Agree.  It feels analogous to choosing lesser pain.

> Well, actually, using a closer bracket to remove one level of brackets isn't really a hot-key use (how I understand it), it's just a different semantics of a regular key in a specific context,

Thanks for the reminder.  I'm still getting accustomed to remembering
that Cmd is no longer necessary, which I do still like.

> I think. So maybe just add a universal "closer" hotkey and keep the existing closer brackets functionality?
>
>
>
> No strong opinion though :)

:)  I'll give it some more time, hopefully I'll be able to learn it
better.  But, if not, just a warning that I _might_ haggle to bring
back toggle as a preference.

 - Chris