In dual wielding max artisan battleswords they get up to 86 - 114 dmg with 44% crit, I dont see dual wielding any blunt weapon near that level.
perfect battle swords only hit that hard on basic attacks. smash, windmill, etc. (the attacks that matter) are calculated by adding both weapons' damage to the damage from your base stats and skills.
base max damage for windmill with dual battle swords (with perfect artisan rolls!): 54+54+60 (from artisan str) = 168
base max damage for windmill with dual warhammers (no artisan rolls required): 87+87 = 174
dual warhammers have higher damage, blunt mastery gives more damage than sword mastery, and giants get much more str.
this is not even accounting for the fact that blunt egos are much more poweful than any 1h sword ego.
giants don't "need" a damage buff to completely outclass humans. they already do.