I'd like to see a new rally point type added to the existing Normal, Fleet and Auto Attack:
Forward. All it would do is simply assign another existing rally point to the autopilot of any ship sent to it. That's it. No special patrol/attack logic or anything of that sort required - just a simple redirect.
With this simple mechanism we could implement basic patrols (have two or more waypoints forward to each other) or just define more specific/controlled paths in general. It would *seem* to be a relatively straightforward thing to implement and wouldn't involve AI. If possible, it should probably be added to DL as well as DA.
Myself, I'd like to see round-trip airfare