I wish section markers showed their depth and distant depth when selected, maybe as a ghost with their handles. Pretty much like text shows the handles when selected, even if it is not set to display the box.
Having 'working' View Sets with textboxes, section depths, hairlines etc. is the way to handle this today, but the depth and distant depths of all the sections and elevations end up creating an unintelligible mess of crisscrossing dashed lines all over the floor plan --so that even in a 'working' View Set you end up getting rid of those sections depths. Except when you want to check or change one, which is when before selecting it you need to go to Display Options. A default 'show depth and handles when selected' would avoid one rather redundant step there (and another one on the way back, once you've checked/modified).
I also like this one and the thought behind it: eliminate as many clicks and menus as possible in the interface. The ArchiCAD 9 update did a lot of this kind of thing and it made a huge difference in everyday productivity.