What functionality is missing? What is unsatisfying with the current situation?

When you have multiple authors and editors on a world, it is sometimes hard to keep track of who added what, who changed what, and/or when something was last changed. With the frequency of the autosaves (which are great), it does get a little daunting to try and keep track of changes that have been made.  

How does this feature request address the current situation?

A changelog, or a log of edits, would allow for authors and editors to work together and to track the evolution of an article, or even to backtrack to a previous version if possible.  

What are other uses for this feature request?

Using it to track changes. Using it to rollback an article to a previous version before a major edit. Using it to know who wrote which part.