Mace has a better selection of non-physical attack type weapons. Low-mid ranks, backhand with mithril warhammers or copper prods destroys those pesky dark-elves and arials that just dodge everything else.
Both are primarily strength based specs
There are edges to get a bleeding affect on a second boneshatter
I think you are right on whirl
Maces probably parry a little better, but not by enough to make or break a character.
Cranial seems to fail less often than pincer to me, but cranial lag can be partially mitigated by helmet type (armor vs. treasure or clothing). Personally I felt being two or more sizes larger increased the knockout chances, but that could just be observational bias.
