We are now on our third upgrade of Tridion Docs, and some very basic usability issues persist. I see very few usability improvements, and in fact have lost efficiency in some areas.
(Issues such as: too many clicks to do something basic; lack of batching in many repetitive tasks; basic window behavior; the interface lacking keystroke navigation/input options; many non-intuitive interface elements/behaviors. In general, things that add up to wasted time and frustrated users.)
Please don't ask me to list the issues. if you conduct basic usability testing, you will see them.