Sorry for the inaccuracy.

I read somewhere that the Ribbon came about because people would routinely request MS add features to Office apps. The problem was that the requested features were already present, but the users didn't know how to find them (or how to press F1 either, apparently). The Ribbon is an attempt to reduce the number of menu levels needed to reach a feature, and to make them more visible by adding icons to the text descriptions. MS says it's easier for new users to learn than the old menu, as you noted. Problems arise when it's installed for some experienced users.

I don't have an opinion on the Ribbon's ease of use. I personally didn't have much problem with it, but I can see how others might find it ... disturbing. i certainly found it an easier transition than W7 and Aero to W8 and The GUI Formerly Known As Metro.