Description of problem: A desktop-effects cli tool is needed to disable compiz. An use case is that the user is unable to disable compiz via the desktop-effects gui because this freezes the system (i am going to report a bug on this). So the user may want to switch to a console (CTL ALT F2) and run something like desktop-effects --disable-compiz. This way, he does not have to tinker around with config files that desktop-effects modified.
This looks to me like too complicated solution. Wouldn't just starting new Gnome session (select different session in the GDM menu) be enough?
Or even better. Log out of X session and then in console run gconftool-2 –type string –set /apps/gnome-session/rh/window_manager "metacity" I don't think creating a special application just in case compiz is broken is good idea. This is NOTABUG. If you see any reasons why there is real bug (aside from the compiz one, which is not the issue here), please reopen with additional information.