I don't have any complaint with your proposal, but it sounds like what you need is a makefile or script to insure groff runs are done the same way every time. More simplistically, you can define a shell alias to invoke all preprocessors: "alias groff='groff -k -e -p -t -R'". (Or name the alias something like "allgroff" if you want to easily be able to run the nonaliased groff sometimes.)
A switch to run all preprocessors still won't catch other necessary command-line options, like macro packages.
