The solution I've occasionally suggested is to set
up some sort of system
whereby the meaning of categorization could be encoded right into the
category link and understood by the software. That would allow all the
different meanings of categorization to coexist. So for example the
article
[[Io (moon)]] could be [[Category:is-a:moons]] and
[[Category:related-to:Earth]]. Or Category:Writers could be
[[Category:is-a:people]] and [[Category:related-to:writing]].
The categories already do co-exist, and there's a simple way to determine
which type a category is. If the category title is plural, (people, moons,
planets), then the articles or subcategories form an is-a relationship. If
the category title is singular, (writing, Earth, Environment, History), then
the articles or subcategories form a related-to relationship.
All that said, there definitely needs to be more support in the software for
is-a relationships. For instance, there should be a way to get a list of
articles which fit into the category or any of its subcategories. This
would be a good step toward replacing lists (though there are still other
features which need to be addressed).
Anthony