I like to always show multiple panes in the left zone Inspector, like I/O, inserts, sends and track versions. I wish there was a way to not show all 16 insert slots and all 8 send slots per track, as I rarely use that many, and it occupies a lot of screen real-estate in the left zone. If I could have an option to shrink some of these panes to show only the slots I need, I could have space for more left zone panes at the same time, without scrolling 
Three ways that this could be implemented, with inserts as an example:
A) A simple static option to choose how many insert slots to show. Or a more dynamic option of how many to show at minimum, and then expanding as you fill them up (always showing at least one empty slot at the bottom).
B) Like the mixer window, the inserts pane would always show the actual number of inserts on that track + 1 empty slot at the bottom. This would save as much screen space as possible for each track, but also cause the panes to differ in size when jumping from track to track.
C) An even more direct mirror of what the mixer window is showing, based on the active project. Meaning, if you have three inserts on tracks 1–3 and five inserts on track 4, the insert pane for all four tracks would show six slots in total – exactly like the mixer window. This way, the insert pane would stay the same size when jumping from track to track – until you insert an additional plugin on track 4, raising the maximum of track inserts from five to six, resulting in seven visible insert slots on each track.