There was a discussion about whether we could/should install & turn on the new VisualEditor. It's at http://www.mediawiki.org/wiki/Special:ExtensionDistributor/VisualEditor with a sandbox at http://www.mediawiki.org/wiki/Special:VisualEditorSandbox. I'm filing this bug so we can actually track what is needed to a) deploy on wiki.ozillam.org, b) get feedback from a broad set of users and c) decide.
http://www.mediawiki.org/wiki/Visual_editor I haven't found any info indicating whether a user can or cannot choose to use the old editor instead. I'm not finding anything right on the editor page, but maybe it's hidden somewhere else (like a user preference or something). Best bet will be to deploy this on wiki.allizom.org and see what folks think of it. As for (b), we can test the waters a little bit by linking people to the sandbox page.
I read this more carefully... this extension does not add the Visual Editor. All it does for now is to create a *sandbox* page where you can *test* the Visual Editor... you can't choose to edit a page with it. :) Given that, I don't see it being very useful to us... you can accomplish the same testing straight at the upstream sandbox. I'm going to close this out for now, and we can revisit in a few months when it's a bit more prime-time-ready. Also: From a quick scan of the specification, it sounds like they're intending for both the current ("source code") editor and the new visual editor to both be available... and for the Visual Editor to become a stock part of Mediawiki later this year. We probably won't ever have to install this plugin, just upgrade to the current version at that time.