We had killshooter turned off in AvA for most of a year....maybe even longer. One night the MAs were down, the crowd moved to AvA and found that killshooter was turned off, and the mayhem began. Skuzzy turned it on there the following day, and we have rarely turned it back off.
FWIW, it really doesn't make a huge difference, unless you're in a big bomber formation, like the scenario guys have been describing for the past few weeks. Assuming that you aren't out to be a spoilsport, it keeps you from trying to fire past a friendly who's already on an enemy's tail, and possibly makes you hesitate just a bit longer in a furball before you press the gun button. It was those little extra touches of realism that converted me from being an initial skeptic to a supporter. I don't really miss it, though, and I haven't heard a clamor for its reintroduction in AvA.
- oldman