On: Eshell as a main shell

[TeMPOraL]

> having a combined buffer list of shells and editing windows just adds to the context switching overhead

Bind that to a key:

  (defun my/list-shells ()
    (interactive)
    (ibuffer nil "*Ibuffer - shells*" '((or (derived-mode . shell-mode)
                                            (derived-mode . eshell-mode)))))

Also, start using the built-in ibuffer instead of regular buffer list, if you aren't yet.

  (global-set-key (kbd "C-x C-b") 'ibuffer)

> maybe something like separable workspaces that have independent saveable and restorable configurations

This probably could be handled with one of the couple windowing/"desktop configuration" management packages available on MELPA, but I haven't used any of them so I can't recommend any. Myself, I use a tiling WM, so I just place Emacs frames where I need them and keep them there.