As it is, bludgeoning weapons are typically a better choice because of how prevalent piercing/slashing resistances and immunities are on mobs. (Skeletal ones mainly). I suggest that more mobs have bludgeon resistance to curtail bludgeoning weapons always being the better choice.
Diversity of challenges is good, but bludgeon weapons tend to be inferior to slash and pierce already because of weight, crit modifiers, etc. so there's a balance issue at play.
I'm fairly sure this is why bludgeoning weapons are, as a rule, weaker than slashing weapons. They're better at penetrating damage resistance.
I mean, are you really going to take a sword to that monster of bone or stone?
Yup.. as a whole, bludgeoning weapons have lower damage, higher weight, and lower crit range than say, an Axe or sword, their benefit is that there are fewer enemies which have resistance to them, Skeletons especially (non PC animated ones atleast) have very good physical immunities, especially to Piercing.
Just for the sake of argument, what bludgeoning weapons are vastly inferior to their slashing or piercing counterparts, outside of the lack of a rapiers/scimitar/falchion type bludgeoning item with high crit chance? Weight is certainly a very subtle factor of balance that probably doesn't come into affect for anyone who cares what weapon they're using.
Great Maul is exactly as strong as a great axe mechanically
Warhammer is exactly as strong as a battleaxe mechanically
The only difference is damage type. Bludgeoning weapons are not innately inferior, there are some that are especially weak but you can find that in any piercing/slashing category as well.
greatmaul weighs 12 lbs, which is less than roughly 80% of all large weapons and also bypasses more immunities while otherwise has the mechanical stats of a greataxe
I don't think this really matters. Nitpicking over slight balance against npc spawns is silly, and would take a good amount of work better spent on new content and such I think.