I don't think that a very big axe and a very big warhammer have that much difference concerning the area you hit with... and if it made such a huge difference two handed and bastard sword would have to hit any time, except your opponent was built like a disc
Anyway, I didn't want to start another How-would-it-be-in-RL discussion about weapons, which none of use have ever used against creatures that don't exist...
I meant that a double axe is the slashing-weapons pendant to a warhammer. Both are slow weapons,compared to one handed swords/clubs, but do a lot of damage when hitting, so imo there shouldn't be such a big difference how often you hit. Damage wise, I don't mind huge differences at all
(although there are already so many monsters favoured by concussion weapons...
)