MS Office UI peeked around versions 97-2003 or so. Everything in a menu, actions grouped / categorized so they were easier to discover. QUICKLY accessible by underlined keyboard combinations (alt+menu letter THEN item in menu letter) and with any actions that had a direct keyboard shortcut annotated. Everything easily discoverable.
Ribbons, I've no idea how the categorize what's popular or not, but 'related' things seem weaker to me, and the context switch price is much higher. Plus there's a need to hunt and kill with a mouse instead of direct with the keyboard.