Hoi,
The good news is that the interwiki tangles are a big improvement over what we had. Now there is clarity when an interwiki is wrong. There is one place where to solve it and when solved, it is solved for all linked Wikipedias.
The problem I have with all the ontology issues is that they are relevant in the context of interconnectivity between systems. This becomes increasingly irrelevant as we identify the records in other systems. Irrelevant it is also because we do not use it. Getting data from external sources is largely frowned upon.
As it is, we are building the data in Wikidata ourselves and comparing things is an afterthought. Many statements in Wikidata are problematic but they have the saving grace that with more statements it becomes more clear what works and what does not. As long as people talk in terms of ontologies and do not translate it into "Reasonator" like application it is in my opinion a waste of breath.
Thanks,
GerardM