Is there a way to disable the new edit filters UI on a per-wiki basis? Or is there a way to make it opt-in on a per-wiki basis?
Topic on Talk:Edit Review Improvements/New filters for edit review
You can use Special:GlobalPreferences. That new feature is not on Wikipedias right now but available on all other wikis.
I think Kaartic is asking something different: whether a whole wiki can opt out of the feature. What I'd say about that is that If there is a special reason why the New Filters cause problems on a particular wiki—a common gadget or some such—we can delay release on that wiki until we can fix the issue.
We can examine the case to delay the deployment but while the feature is default since 8 months on Recent changes (and the discussion is about that), we will need a special look at the causes.
As the upcoming Watchlist update would have the UI similar to the RecentChanges update, I don't think the discussion is limited to the RecentChanges UI update. The people involved in the discussion referenced before are concerned in general about both update.
IIUC, one person was especially concerned about how the RecentChanges update hid an important notice for new comers and anons behind "Other review tools".
I thought a way to disable both the features per-wiki would be a temporary medicine to the concerned community until they reach a consensus that the new UI update could be used for all users.
All messages on MediaWiki:Recentchangestext
can be moved to mediawiki:recentchanges-summary
, so that they will always appear on top of the page. MediaWiki:Recentchangestext
should then be used only for things related to the RC page. This is not a blocker per se.
I've mentioned it to the discussion after 5 edit conflicts. ;-)