I think you should insert in the repositories this GTK patch, and the relative gnome/xfce applet, that moves the menubar at the top of the screen (like MacOSs).
The global menu can be easily activated and deactivated by removing
The new user shouldn't obviously be forced to use it, but adding the applet to the panel (maybe marking it as 'experimental') would give an interesting feature, and will help to spread the word about this great project. If the applet is not activated, no UI changes are made.
The size is very small, the GTK patch is only 50 lines of code, and the applet is very small.
I actually use the global menu bar, and I find it faster and easier to reach.
Just my opinion.