i'll note that man(1) does support -a in its normal "view the manpage"
Yep, I use it all the time :).
i don't know how hard that would be to emulate in info(1),
It makes no sense to do so. man is fundamentally a non-interactive
program that outputs to stdout. As I said before, info is an
interactive program that brings up one info page at a time, it doesn't
pipe through $PAGER.
It only makes sense to implement -a for non-interactive usage.
Anyway, clearly Sergey is busy with other things. I'll try to take a
look or at least put it on the list for the future.
Best,
Karl