With all the different package managers out there, it's just not much fun to keep track of all the rules and special cases for each tool. Better to just have a "--rollback" option.
Isn’t this solved more generically by version control? As long as your package manager uses files to control the packages searched for, them you commit those files between upgrades and revert them to rollback. nix handles this at the system-level by making your system configuration match a declarative specification.
