Actually, while crossbowmen do use that tactic, only archers with balls do the same. Unfortunately, ball-less archers are the common folk around, so you can see them employing the run-like-a-chicken tactic far more often.
Xbowmen don't need to put point in PD, they have more skill point to put in melee fighting skill like PS/Shield.
We can call archers ball-less but in fact they are skillpoint-less for sure.
Xbow has always been favored since the begining of cRPG, dunnon why but it's the only thing that is balanced with realism (anybody can shoot with a xbow, peasant can, there is no need of training, etc = ingame : no need ofspecial skill except STR to use a xbow).