It seems to me, from outside, that the term "mostly-hierarchical" is the killer.

Fitting data that is "mostly" into a structure, is very hard. The advantage of tagging is that it is so unstructured and dynamic.

I'm over-focusing on that term (likely because I have taken a position, and feel like I should advocate for it). But I think you've just torpedoed the idea that there is a Linnean taxonomy good enough to hold everything.

But that creating a dynamic, editable, personal opinion web page that shows the data through a taxonomic lens is also very useful as an additional resource. A resource that should be featured - but may not be controlling.