Hehe, It did take a long time to get used to it, by necessity of "where I work upgraded, so no choice but to work with it". So, now it's second nature, and in my brief interludes with LibreOffice I struggle with the layout style and finding where things are.
I did say "But then I'm not sure if that was just a case of getting used to the new layout" - still open to that being the case.
Maybe it's like 12th edition text books, change for the sake of change. In the case of Office software, we need people to keep needing the 'basic' and 'intermediate' training sessions; we need credentials to justifiably decay with time?
For me, the Ribbon is what made Office unusable. I've used MS apps since the MS-DOS and Xenix days. I remember the old MS menus (2 lines, bottom of screen, summoned with Esc) to CUA transition, then the horror of WinWord 1, then the passable WinWord 2, then the actually quite nice WinWord 6.
I still run Word 97 on Ubuntu under WINE. Works perfectly.
But after Office 2007, it is totally unusable for me.