I'm going to go as far as to say I can't see us supporting this extension any time in the next 12 months. I'm almost tempted to go further, but who knows. A few months ago, I would have said the same thing about Echo.
There are lots of other higher priority things on the list for the foreseeable future. Working out how we install and manage Wikibase for the ShoutWiki setup isn't something we can commit to at this point.