I like the idea of using
https://www.mediawiki.org/wiki/MediaWiki:Cirrussearch-boost-templates more
extensively, for both positive and negative boosts.
E.g. compare that to Wikitech's more extensive usage:
https://wikitech.wikimedia.org/wiki/MediaWiki:Cirrussearch-boost-templates
(Docs:
https://www.mediawiki.org/wiki/Help:CirrusSearch#Boost-templates )
Perhaps we just need to apply {{historical}} more widely?
Or maybe we need a new Header-template that's distinct from {{historical}}
and {{outdated}} and {{fixme}} ?
The current list of related and widely-used templates is under
https://www.mediawiki.org/wiki/Documentation/Style_guide/templates#Fixme
I think tagging pages is slightly preferable to moving pages, because it's
less complicated to undo, and still leaves content accessible to a basic
search (just further down the results), and to different use-cases (per
Gergő's comment), and doesn't get technically semi-blocked for translated
pages with >500 subpages.
However, it is more labor-intensive for pages with many English sub-pages
(i.e. needing to tag each individually), although I'm not sure how to
evaluate that issue, without preemptively seeing the massive list of the
pages that ought to be deprecated!
I'd recommend: Tag a few dozen pages, and simultaneously create a listing
of pages where tagging doesn't seem sufficient, so that we can discuss more
specific examples/buckets of examples.
E.g. you mentioned [[Help:Extension:WebFonts]] as a candidate for Archival,
but perhaps that could be handled in the same way as [[Extension:WebFonts]]
itself was (blank and tag it with {{archived extension}} )? Plus I just
checked, and that page has over 500 subpages (from translations) so it
would require dev assistance to move!
The other semi-related problem this all makes me think of, is the cleanup
needed in
https://www.mediawiki.org/wiki/Special:PageTranslation to
"discourage" any outdated pages. I'm not sure how extensive that problem or
overlap is, but ideally anyone doing cleanup of one problem could also keep
in mind the other.
Hope that helps!
Quiddity.