My main criticism of the ribbon is how it radically changes its structure when the window is resized. This creates menus out of formerly top level elements etc.

My main criticism of the ribbon is how it radically changes its structure when the window is resized. This creates menus out of formerly top level elements etc. Thus, Word at half screen width is a radically different UI than at full width. Then there are these almost invisible buttons next to the bottom group labels. Some features are hidden behind those but there is no good visual indication that these buttons open dialogs related to features the group. So I am not totally convinced that they are the best in this field.