There is a proposal for the upcoming Mediawiki Dev Summit to get us "unstuck" on support for non-linear revision histories in Wikipedia. This would include support for "saved drafts" of wikipedia edits and offline editing support, as well as a more permissive/friendly 'fork first' model of article collaboration.
I outlined some proposed summit goals for the topic, but it needs a bit of help if it is going to make the cut for inclusion. I hope interested folks will weigh in with some comments on https://phabricator.wikimedia.org/T113004 --- perhaps suggesting specific "next step" projects, for instance.
Thanks for your help. --scott