The two-step movement-disc system is indeed a good idea. I’m not advocating against it, the system is clever and not without virtue.
The issue is the disc is drawn around the moving unit. The center is on a point in space from which the player moves away. From a human-machine interaction standpoint, the point of reference is irrelevant, if not to highlight the moving unit.
The problem with this is that navigating becomes progressively more difficult the farther you move away from your original position. Especially in respect to the z-axis. The current system is biased towards very shallow angles above and below. Distance is the system’s Achilles heel!
In order to move accurately, you have to completely rely on reference points on the x-y plane in the sensor manager. And even then you still have to painstakingly align the camera in two or more different angles in order to navigate accurately.
Of course, this is the only way to navigate in the fog of war.
However! in most cases you wish to move your units to a position relative to a target. Friendly, or hostile. In this use case, it is more efficient to draw the movement disc around the target, and not the origin. It has the benefit of moving to a location relative to the target with absolute accuracy in exponentially less time.
Moreover, drawing the movement circle around the focused target allows to player to move or jump distant units outside of the sensor manager, via control groups. Even inside of the sensor manager this will allow for easier navigating inside 3-dimensional space. Simply because you can begin plotting from a focal point closer to your intended location, and with greater accuracy. And so, it’s Achilles heel is no more.