Attack zone

It would have to work like an area-patrol though, probably with some element of randomness (or some way of drawing out the path, effectively undoing the entire ordeal), otherwise it's basically increasing the targetting/detection range of any unit it gets used on.

You're just best off a-moving around the area in a circle or two, splitting units up to a-move to different points, and/or watching what you can and clicking directly on it. Microing units in small groups after a-moving multiple segments of your army, or stutter stepping enough to get all your ranged units in range (ideally you should pre-concave around your opponent so you don't have to do that) is the most effective way to fight anyway. A-moving is generally bad because units don't prioritize units they counter or kite their own counters, and they will overkill targets.