Sorry about a blank subject before...
Came across a good CalTech presentation called Relevance of Topic Maps
The presentation has the infamous Cregan datamodel on page 5. The question is why not use this already-certified ISO datamodel being mapped to RDF somewhere -- why not IT be the foundational conceptual model of Wikidata? Topic Map API could be built into the WOM. It's a good initial architecture for a cognitive model to interact at the human level and the data storage model at the triples level.
I like SKOS and Dublin Core as core ontologies for Wikidata. SKOS is a subject index and Dublin Core is the index card. SMW subobjects like fullpagename#fullpagename expressions can be (have) a (the) Dublin Core set of properties; this design satisfies directly the needs of RSS folks an importatn requirement.
Maybe melding Topic Maps, RDF and Wikis might boost web semantics by creating an orientation towards understanding pithy lexical language expressions common in subject headings. Doing so would be a major practical milestone to achieve alongside semantic infoboxes -- that might create a bit more buzz than "formalizing the adoption of database technology" would, in its own right (I say this with reference to Ward Cunningam's latest interests). Essentially it'd be great to integrate wikidata topic maps with (group) mind mapping contexts - another natural fit that so could rock.