apt-get rollback <packagename> !?!

[David Baron <d_baron@012.net.il>]

It can happen, even to the best, even from "stable"--an upgrade is done that 
renders the system less than usable. It just occured with X.

While, if one really knew how, one could bet stuff from backport, compile it 
(assuming all goes well--remember other things were changed in the upgrade as 
well!), and have a fix, well, most of us will simply be stuck. This could 
presumably be done manually if one has backups but apt-get knows how to 
handle these things in a correct and complete manner.

I propose a rollback capability in apt-get. Assuming that this could not be 
done over the internet at present, it would involve maintaining an archive of 
replaced items and the dependancies.