Bullshit marketing
It's the nonsense bullshit marketing justification that comes from MS that's most annoying....
I sat through a presentation where MS "justified" the new ribbon interface by enabling every toolbar possible in MS Word 2003 and compared this with the new ribbon interface. They weren't impressed when it was pointed out that only a fecking retard would enable every toolbar simultaneously and some of the toolbars would normally only appear when required.
There are some good things about the ribbon interface - as in the functionality is usually better grouped than the often irrational placing of menus in the old MS Office (menus that were compounded by the idiotic default of hiding everything that isn't used twice a day). What Open Office did for the menus was to keep them largely the same but rationalise the placement of some items - the effect was an interface easy to use and familiar but with improvements - i.e. evolutionary. Bringing in the ribbon interface at such a size was a bad move though as it takes up so much vertical screen real estate on a lower resolution screen that it severely impacted usability - and if the horizontal space wasn't great either than many functions were lost in a 3x3 pixel drop down that was far too easy to miss (Office 2010 improved on this with some smarter collapsing).
Usually though, with the entire Office suite, the only thing that changes is the front user interface. Frequently exactly the same unfixed bugs are present and many of the settings popups are identical. While there is some merit in not fixing what isn't broken, when these screens are the setup windows of Microsoft Outlook, this really doesn't apply.
Given how pathetic the Metro interface is and that MS Office 2013 is bound to ape it's look and "usability", it's no wonder that MS have been hiding the new version. MS Office is their big cash cow, breaking it is not something to be done likely but if a homicidal user-interface is being championed at the upper level of idiots then, especially at a company that runs internally like MS, this is what is going to happen and nobody will dare to speak out about it.