It would be nice if users and developers could designate certain preferences to automatically apply across all wikis. This will require A Lot of Work™.
Extension:GlobalPreferences is a rough draft of the functionality.
Challenges to overcome:
- UI language:
- polyglot users who want UI & content to match, and
- cross-wiki maintainers who want to force the one UI language globally T16950#2187671
- Gadget on/off pref - T16950#2188222 (and possible security issue with assuming global - T16950#2188400 )
Related TechCom-RFC: T64559: Redesign Special:Preferences (tracking)