I can handle the changes and like you I don't use FF much. However the issue is with my wife and her phone, she had this update forced on her with no option to refuse and it is a Beta as well! She is severely dyslexic and has real problems identifying symbols so much that she has over the past 3 years of using a smart phone taught herself to remember that a certain part of the screen performs a certain action (the actual symbol is to her is irrelevant) and on top of this the new UI has such small icons instead of the TopSite ones before even I struggle to see them on a 10inch tablet. There is nothing wrong with the current UI and they are changing in my view simply because they want to, many of the changes in this release could have been done with only minor changes to the UI. This is going to be a real issue for people with sight problems or dyslexia.
Stuart