Hopefully this will help to end the madness of Global menus coming back into the mainstream (at least in linux), they save absolutely no space (despite what some may think, they only give the appearance of saving space on macs because of the difference between 16:9 and 16:10 monitors, while not actually saving any because you're using a line of text regardless, moving the panel over onto the left or right side and putting the menu bar in the title bar does however save vertical space) and make it more difficult to deal with more than one application at a time, and causes extra mouse travel with applications that aren't full screened while providing no benefits over menus being local to the application.
Heres how i imagine unity: http://s30.postimg.org/eai8wk9s1/Unity_Blueprint.png
Side bar and top autoajust depenidng how many icons they are holding, and when a window does fullscreen side bar hides.
Right now theres alot of wasted space and this would be the best case senario in my mind.
I'd prefer for designers and developers to put more effort on side menus instead of the traditional top-down menus since all mainstream display resolutions have huge amounts of horizontal space but just too little vertical space to spare.
Something like a ribbon but on the side will work well.
It's common nowadays to come up with one usability solution at the expense of another currently in use, rather then making the new one coexist and/or allow for an easy switch.
To be honest I don't see how the global menu provides any usability benefits, as opposed to being a complete negative in terms of usability, which is why the concept had died and been buried (other than on MacOS and OSX) until Shuttleworth decided to chase after apple and bring that in, although I honestly don't get the obsession with vertical space (which again it doesn't help) and killing the menu bar. Sure there's more touch friendly ways of going about menus but touch based devices should really have their own dedicated UI. That said Tabbed Toolbars (aka Ribbons) are a good idea because it allows task separation of controls.