Crossbows were devastating, mostly because they were so easy to use. Someone with almost no training can turn a crank, insert a bolt, point, and trigger the release. They were regarded as cheating on account of using mere peasants in capacities that should have required bowmen with years of experience. Ranged weapons are overpowered, always have been, where modern equipment is available, melee weapons are basically only used in situations where the victim is not expected to be able to retaliate or even defend themselves. The ancient romans were famed for their javelins, which infantry would use to give themselves an advantage prior to engaging in melee. One-on-one, a crossbow should almost always defeat a melee, but in large groups the crossbows can be overwhelmed and closed with, at which point they should be at a disadvantage. One thing that might work would be choosing the target several frames in advance, to increase redundant fire...
I believe that you can weaken crossbows, generate a world, and then return them to their original stats, thus reducing their impact during world generation while having them operate normally in fortress mode. I am not a big fan of changing them to bludgeoning. Piercing gives them a high chance of fatal wounds against large living targets. So they are highly effective against the most common and dangerous opponents. But I can't help bt suspect that giving them bludgeoning damage changes them to be less effective against many opponents, but to make them effective against all opponents, so that instead of needing a backup plan for the metabolically challenged, you just need more bows...