I think that the blobal menu isn't really a problem for most of us for a simply reason: most of the apps doesn't really use the menu as an important part of the design but they preferr toolbars, button...
Only a few, but important, apps still use the global menu first LibreOffice but for it the app menu isn't activate.
Now we should find something to replace or redesign menus, there are some mockups here https://live.gnome.org/Design/Whiteboards/Menus, but also developers should adapt their apps to the new design.