I think it is very difficult to change the skill system, although WSE allows amlost everything.
I can't really tell anything about the difference between horse archers and horse crossbowmen, as those classes always seemed equal to me, if anything the horse archer still being slightly favoured, as a lot of fast shots with less damage are to prefer over few, slow and powerful shots, in my eyes, as it is also important to regularly interrupt the enemy, and the results will always be closer to the statistic middle (?), chances are much lower you will have "bad luck" with your shots.
I think if the recent archer nerf will be reverted, everthing will be fine again, anyway...
