I didn't see a complaint in here? @proavia brought up an issue he experienced and some provided "work arounds". The thing with using others UI, if you change the style and there's an update, if the changes aren't noted somewhere they may be lost. There is, more than likely, a whole ton of things that can be done on the back end. It's, generally, just knowing where to look and how to change them. This site has had Xenforo for a relatively short amount of time so Leebo may still be "kicking the tires" so to speak. It'll get there one day.
The compliant is that the new UI jams all the information into the left side of lines in thin fonts and leaves the right side of lines blank.
It is a poor use of screen real estate, slows readability, and productivity when reviewing the thread lists.
Some UI designer optimized the style sheet for wide screen devices as though it was a narrow screen phone. This is going backwards from what a responsive website should be doing to accommodate different form factor devices.
I will be happy to implement an improved style sheet if allowed. Otherwise I need to use what is served even if a step backwards.