i think plenty of ppl answered about this before. there are not diference on crit power between sword or blunt at least not to my knowledge, the diference is on the "randomness" of that damage, lets say sword hit for 100 crits for 200 comparing to this blunt can hit for 100 +/- some damage meaning the crits can also be +/- some damage comparing to the crit when using sword.
blunts by itself should not have higher crit dmg then swords, they just have the potential to achieve bigger damage due to the "randomness" of its damage.
buffs such as zealot and angelic icon etc yes does are the ones increasing the crit power when using blunt.
if im wrong please feel free to proove it.