> I suspect you are correct. The big question I have no answer about is what percentage of users was good with the old interface. If it was <10%, the ribbon is definitely warranted. If it was >80% ... maybe not so much.

My experience is that number was probably way lower than 10% -- basically, most people use Word as glorified typewriter. They do know to change font, and that's it. They indent/center text by inserting spaces in the front. They have no idea how to insert image..