As started here http://ux.joomla.org/forum/Joomla-30-Administrator-Template/648-Save-Save--Close-Apply-Update-Autosave-etc-etc?limit=8&start=16#771 I really have given an option for UNDO a thought.
As I understand, the database is holding the info about new text, layout (font and picture size etc)
I'm a pure amatour and only work with Joomla from time to time.
My guess is that there must be many out there like me, that from time to time are "a bit to creative" and wish they had never pushed the "save" button.
Wasn't it possible to somehow save the info in cahche (or make a backup site) so that you could always go "one step back" - like the CTRL + Z button in Windows, Words etc.?
My guess is that a lot of starters/amatours like me would be very pleased of having this opportunity to bring the edited page back to "last edition" without having to upload the database (if you saved it)?