The trade offs between x-bows and regular bows is distance, speed and training time. X-bows are slow and short ranged but pack a massive punch in their range also it takes far less time to train someone to use a x-bow. A bow requires longer training time but has a faster rate of fire and an extended range. To make them realistic make it take longer to train an archer and give crossbows a shorter range and slower rate of fire.
