One main use-case I hope we can consider/solve, is that of: Documentation page redundancy/forking.
- to have m:Help:Link (/de /fr etc) as the central page,
- which is transcluded to w:Help:Link (etc: d:Q5257102)
- but where local addendums can be inserted. (ideally at a per-section level, to allow hatnotes and other complexities)
This would (mostly?) solve the issue of "important updates need to be done at every wiki, but rarely are", and get more editors collaborating on improving the core docs rather than focusing on their home wikis quite so much.