You would not need to be able to edit the offline file. Instead it could still be just a link to the online version of the file, like it is now. But additionall

You would not need to be able to edit the offline file. Instead it could still be just a link to the online version of the file, like it is now. But additionally it could contain the actual data that can be imported back to Google servers when it is accidentially deleted from the server.