Hey,
Heads up that it is a possibility that Trevor's Drafts extension may be enabled after it is reviewed. I wanted to bring this to the attention of the design team just in case it hasn't been mentioned, because it currently adds a button to the editing interface. If anyone wants to have input on this, now is the time to speak up.
As I understand it, this is different than the drafts idea that has been discussed for article creation. Rather than a namespace where pages could be moved in and out, this is instead drafts at the more granular level of individual edits. Drafts are put in to a log, but are individually owned.
Docs: