I dunno if the dmg of normal bolts are worth the reloading time. I tried 2h/arba and found myself running around with 2h way more often than shooting :x
still, they´re probs good for 2h/xbow who focus more on 2h
if normal bolts would need 1 slot, nobody would use em
if 2h/xbow builts are getting too much of a problem, I´d change the dmg gain for +3 items from +3 to +1
and don´t you even think about making steel bolts 2 slot