Aren't there other weapons that are better served for those purposes? I could be wrong, but I believe that it wasn't designed for those purposes, albeit some do use it in that manner. Apparently the main advantage of an AR-15 is that it is semi-automatic, so is it popular for hunting for those less skilled that can't take down an animal in one shot?
I don't know if an AR/AW ban would be effective, but it seems its primary and most effective purpose is for mass killing of humans (or a herd of jack rabbits which would be wanton waste). It certainly has proven its ability to be effective in mass killings, although in terms of total killings a handgun is probably leading.
To me there is a balancing act, a ban on AR/AW sales may, or may not be effective, but by the same token it wouldn't limit someone's ability to effectively hunt or protect themselves.