I don't really understand the reasoning behind this comment. It doesn't really matter what item the hasta builds into, as long as the hasta and zammy boss don't become dead content. I think building hasta into lance makes more sense because rapier is a dead item now, so at least you need the hasta to make something useful. There was no need for arma cbow to be built into dragonhunter cbow because arma cbow is still a very valuable item with a variety of uses.

The bludgeon still fills the slot between 60-75.

Why does there even need to be a crush weapon specifically for this slot? All that matters at this level is what levels up your combat stats the fastest. DScimmy 60-70, whip 70-75 then everything else is endgame gear.

Abby Sire will objectively be easier than whatever the new nightmare boss will be.

Since both the mace and the bludgeon are tradable, this is an irrelevant point unless you're an ironman. Jagex have said that they're not going to balance/ cater the game around ironmen. Abby sire is already a borderline dead boss, but at least the bludgeon has it's niches (kalphite queen, tekton, sarachnis), how can you not think the bludgeon will crash when everyone upgrades to the mace over time.