I actually like the idea of killshooter being off in the AvA, like it is for FSO. It adds another layer of difference from the MA settings, much like the no enemy icons does. It will take getting used to for the non-regulars, but I think it would add to the experience.
Accidents will happen, and there might be those who try to abuse it, but the regulars and staffers should be able to deal with it. I say give it a try for a few days.