It would be ideal to detect when someone leaves the page (perhaps by accident) and have Confluence save the latest draft at the time the user leaves the page.

Remapped short cut keys are one great example of why this is useful. Example of how somone would accidentally go Back in their browser on OS X in Firefox: Apple-Left goes to the start of the line in MS Word & even in JIRA, but when editing in Confluence it commands the browser to go back to the previous page.