from the way i'm reading it, who wants +10% grim damage when you can get a slotted elemental katar with an extra slot for +20% grim damage?
and autoattack might be nice, but in the end it's lvl 3 weapon, 120 damage and 0.5% chance to sonic blow kinda looks meh to me when you could get a 3-slotted lvl 3 weapon with 105 base ATK...