what should we actually focus on?
VisualEditor.
Do everything to ease/encourage contributing content. Having
to install node.js is far too complicated. Could node.js be a requirement
for the web host to qualify as supporting MediaWiki?
Shadow namespace to include Template, Module, Help, etc. namespaces. That is
to have templates available in a way like images are from commons. Most
simple wikis don't have the enhancements available from templates because
it's too complicated to admin, (besides it also being duplication of
effort).
Sandboxing new users so that preventing spam is built in. A recurring
question from new admins is "My wiki has been hit by spam bots, how do I
clean it up and prevent it happening again?".
Include WikiTeX, or something more user friendly. For a consistently smart
and a uniform quality of illustrations on all MW wikis.
Solid way to handle other file formats, i.e. audio and video files.
Semantic web, e.g. for a wiki to include current prices by linking to (where
available) a suppliers database.
Also support MW on economical shared hosting. Specify all the requirements
to host a fully functional extended MW wiki.