Is it? Shortcuts are not discoverable anymore, most actios are hidden within tiny icons (or dialogs full of tabs, oppened from actions hidden within tiny icons), often there is no logical grouping of the actions (ok, maybe the old menu wasn't better), ribbons appear and disappear out of nowhere, and there are hiden ribons that take a Google search to get.

I quite like the "ribbon" idea, but the Office's implementation? I see no reason to think that it's more productive, and I certainly do not feel more productive on it even after years of training.

By the way, MS also had lots of actual user testing supporting their decision to take the start menu away and maximizing every window.