Vectoring thrusters have been requested like forever. I'm pretty sure I was among those requesting, too. That's one of the reason hinges are on the trello.
The mode term you used could be confusing since auto-fire has been used with the game for making part activate continuously. Maybe that should be changed to automatic or AI controlled.
Manual control could be troublesome and confusing to new players. It will be difficult to master due to timing. Unless it's similar to all similar requests reguarding setting rotations. I can see this could be made into a uniform UI with those other rotation feature requests.
One major problem I see is that these thrusters would essentially be roof turreted thrusters without prohibitive zones. It makes them very OP. So to counter that their rotation arc could be restricted and the prohibitive zones created accordingly to the rotation set as discussed above. In this case it would be similar to weapons where the bore direction is set and the actual arc would be fixed to say 45 degrees to either side. This will be tricky to implement the prohibitive zone logic and probably will result in some arcs having slightly less prohibitive zone tiles.
Aside from these naturally, it would be nice to have boost and or alternatively burst mode, too, for alternative medium sizes.
