Well; pulping accumulates exponentially but maces start with larger number and hit with more total force so they are faster. That said, armored enemies generally take more damage from hammers; and doubled weight isn't double damage but is still doubled weight (for the dwarf).
Morningstars, though...Go recheck your raws - they have same surface area as warhammers, are 25% heavier, and will happily sever nerves and tendons (and toes, unfortunately) before converting their impact to larger blunt damage than what hammer provides. Near as I can tell, they're flat-out better (expect for using mace skill), limited mainly by dwarven inability to craft good ones.
When I tested putting down smallest undead before they were made easier to kill, they performed at the top along with whips there too (while some sharp weapons were utterly unable to harm the same enemy). Though whips also have tendency for removing small parts. (I think a third weapon was close, too, but cba to find my notes; testing would have to be redone now anyway.)
Maul you can use bit better with larger creatures (such as goblins' trolls/ogres), and their large contact area doesn't matter as much if you aim at smaller extremities in adv mode, to which they can thus do more damage. Also, since they have more force, they also do more damage by force twisting. I don't see myself using them in fort mode, though.
Giving up a hand is extremely not worth it, as shown by the pikegoblins in fragfish's combat testing. Dual-wielding two of same weapon is okay - against armed opponents good, even - as long as you don't face fire thanks to parry and backup ability. However, one can be buff enough to wield "2H" one-handed, in which case the bigger swords may perform better (more contact area isn't always good; need sharpness to scale.) and pike is flat-out upgrade to the spear.