> has it been considered yet to simply support an optional
>
>   ~/.emacs.d/pre-package-init.el

Yes. I suggested this on a previous thread (before starting this one) and
someone complained of yet another file affecting emacs behaviour. Then I
suggested the streamlined version of that in the first email of this thread
(having a file that delays initialization, but doesn't actually get
evaluated), and the few responses I got still preferred the other option.