Adding to this is the ribbon content is just too busy. It fused icons with labels and stuffed it in some uneven grid. The regular toolbar was more or less even grid, well, a row. The usual menu is also structured on quite uniform grid. It's mentally easier to follow straight lines, we read in straight lines, scroll in straight lines, well, typing too. Yet when it comes to ribbon, the adjustable grid layout makes one adopt an adjustable scan pattern.
I find this pattern quite distracting. Always feels like I'm staring at the old-time toolbar customization dialog, as if someone spilled buttons out of a toolbox onto the screen, and to make it more fun, also mixed them with labels...
Anyone remembers the initial requirement for the ribbon to use the specific font, as it was used for positioning and could not be customized? Not sure if it's still the case.
I wish MS promoted a style-based workflow/mindset more than the free-hand formatting. Perhaps, this would by itself eliminate the need for the busy toolbars, if only during style design.