Jensen Harris has an Office User Interface Blog which explains the design rationale behind the new changes in the Office user interface. One fact that came out in the research was that of all current Office users, fewer than 2% of them actually customize the programs, the other 98% leave it unchanged, or suffer when the default layout is changed through a user error of some kind.
One thing that is very slick is the reference capability within Office 2007. The pieces are there to automatically build a bibliography and references using any one of a number of styles such as APA or Chicago. I was wondering about capability with EndNote, which is the standard for maintaining a list of publications and citations. On the EndNote web page, there is a discussion of Enddnote and Word 2007, and it sounds as if they are on the case. EndNote X will work with Word 2007 and is already compatible with the beta version.