Yeah it's a lousy "argument", just wanted to explain that we too get 1 shoot, probably a lot more then we "1 shot". The biggest problem is, if you "nerf" damage more, we won't be able to kill at all (I'm exaggerating).
I believe "2-hitting" for medium armoured, and 3 shots and above for heavy, is the intention with the arbalest. If you lower the damage output, there will be no reason to take it over a bow. In all honesty, it is very rare for me as an xbower to get that second or third shot in. I shoot unaware non-strafing people over dodging aware people any day, we don't have the luxury of spraying bolts around.. =)