I feel silly about creating a whole topic to address one request, but I think it's a pretty big quality of life thing:

Please add functionality to right-click so that it closes open UI elements.  I am completely spoiled by Endless Space in this regard (the game is a masterpiece of UI design) and the simplicity and ease of being able to 'back out' of anything - planetary government screen, ship design, diplomacy, research, etc - with a single click is something that is very high on my priority list.  I can't stress how much I value this in 4x games.