[x] Wait until that page gets converted to Flow.
[x] Wait until it's possible for mediawiki.feedback to post to Flow on a different wiki.
[x] Wait until it's possible for VisualEditor's use of mediawiki.feedback to post a different wiki.
[x] Message all affected wikis.
[ ] Change the configurations for the local wikis.
[ ] Redirect all the pages.
Steps #4 and #5 are easily reversible, if any given small wiki wants to directly support their own page.
Step #3 needs consensus that feedback can be given in any language if one doesn't feel like using English and/or posting to Phabricator directly. Editors should be aware though that Google Translate makes an awful job when it comes to technical language, and may want to find an intermediary instead to make sure their message is properly understood and triaged.
Once we centralize the feedback pages, we'll be watching how things go, and then re-evaluate the situation after a while.