Let's face it: one of the most annoying things in Stellaris, which could be easily solved, is the unpredictability of border changes. If only we could have some way of accurately measuring a given planet/outpost's border extrusion (even a plain circle like the ones for sensor or warp ranges), we could predict how our borders would expand/contract by a given action. Also, a system for measuring distance (even a rudimentary one like CK2's) could save much headaches with some basic tweaks to the UI.