In terms of an …
In terms of an MVP, it’s probably just documentation and clicking through / debugging. (re: documentation, if we do it in the WIki [ e.g., https://github.com/benbalter/wp-document-revisions/wiki ], I have a script to merge it down into readme.txt and readme.md )
In terms of stuff on my list, I’d love to get at least a few unit tests in there, at least to get it set up with Travis CI (https://github.com/benbalter/wordpress-plugin-tests/), and was toying with the idea of integrating with Scribu’s front-end editing or similar. The APIs already there, and the permissions should work, it’s just a matter of building out the front end.
Last, I think it should be a small lift, but the other feature on my list would be to either spoof or copy over the parent’s revision history on fork (so it’s like a true fork w/ the full history).
Beyond that, I think you might know this space better than I do. You’ve seen the code… what sucks? What’s missing? What feature can we kill off?