Already covered by auto-save in editor so we don't lose work accidentally.

It's not obvious to me that auto-saving and saving-but-hiding-until-later are the same thing. In your implementation of auto-save, will an auto-saved copy serve as a "draft" that we can re-access later (after disconnecting, deleting cookies, logging out, etc.)?
There's no need to reply here, but I hope the features of auto-save are described in a good doc page or blog entry when they're implemented. Thanks for keeping an eye on the feedback site.

This has since been implemented as we now have Draft functionality for pages. Going to update the tag to say it's done.