Oh I don't mind the ribbon (I mean, we've had, what, 8 years or so to get used to it?) or the very pretty GUI updates. I recently installed a demo for a model viewer that had GUI graphics reminiscent of an older Macintosh, with color. My initial thought was "Jeez, if they can't be #*%ed to use OOTB GUI dialogs and made fugly simple stuff like this, what can I expect their dedication to core-capabilities is?" and then I kind of had an introspective moment about judging a book by its cover...
...anyways, my point was less about the introduction of new stuff, which I do accept the value of, and more about the growing INABILITY to easily transition to the traditional. In the case of Autocad, those reliant upon the keyboard for the 99% of commands would surely find that the ribbon is a needless waste of valuable screen real-estate. I went as far eliminating all but one row of toolbars iirc, and no menus, iirc. Palettes collapsed nicely and had the remaining functions.
Anyways.. yea, the crux, for me, was the deliberate EXclusion of 'traditional' UI rather than the introduction of new, which isn't really all that new anymore.