One interface area in Archicad I feel is really inefficient is the current Navigator and Organizer. Especially in the era of multiple monitors its easy to run into their limitations.
I feel the two tools could be combined into one tool named the Navigator. But make it so the four buttons at the top were four independent toggle buttons that instead of changing the state of the current plane, would instead open or close a dedicated plane for the button.
To illustrate, if all buttons were shut off, the Navigator would be one plane wide and blank besides the four buttons. If two buttons were pressed, then the two planes corresponding with the buttons would be open and the Navigator would expand to show both planes. If all four buttons were toggled on then all four planes would be visible and the Navigator would expand to show them all. If one of the buttons was toggle off than the corresponding plane would turn off and the Navigator would contract to encompass only the currently showing planes.
Another feature of the new Navigator is to be able to swap or customize the option pallet beneath each plane. I use options from both the Navigator and the Organizer so this would be necessary.
One final feature but something that would make this very powerful is if the Navigator could be opened more than once and that each instance held it's own settings that could be saved. This would preserve established work flow patterns in AC and it would be possible to dedicate Navigators to certain tasks.
For instance, a recent topic I participated in reminded me how much I wish I had a single plane pallet separate from the Navigator that showed the saved views plane I could keep docked and would remain visible and unchanged in the interface. I really use saved views a lot but I find that even tho I have the Navigator and the Organizer open all the time, I'm constantly switching the current planes on both tools and it seems so unnecessary, annoying, and time wasting. But I want this single-plane-saved-view-Navigator on the monitor I'm doing my modeling and the improved all-four-plane-open-at-once Navigator on the satellite monitor.