I am unaware of any two-handed piercing melee weapons, and I feel that's kind of unfair, so I'm suggesting at least a spear. I don't mind if it uses the same animations as the quarterstaff, I would just like it to be there. If you don't think a halberd or trident would be too close, they could have their own weapon classes as well, like the difference between a greatsword and a falchion. For a little flavor, maybe a lance(like a jousting lance, not used as another word for spear)? I don't think a two-handed pick would be much of a stretch. Scythes could even be counted as piercing weapons, if you wanted.
Anyway, thank you for your time. I know you're already working hard to improve the game, and I appreciate it.