Have you been changing the vocation of you and your pawn to match the weapon you want? Have you been purifying your lvl 2 weapons as well? This can effect the predetermined pattern of what weapon you'll receive.
Here
Edit:I never confirmed this, but I still think the sidequests from the request boards on BBI are somehow tied to what you can purify. I killed Daimon 35+ times and got nothing but head and leg armor from the lvl 3 cursed armor (no arm or torso) and a handful of the same weapons from lvl 3 cursed weapons. I desperately wanted a Revenant Wail and but it never happened. I stopped farming Daimon, collected and completed most of the sidequests from the BBI boards (that means ALL the request boards, don't forget the ones in the sanctuaries within BBI) came back and got entirely different types of weapons and armor.
If you're desperate, its worth a try and will get you away from the grind. Some of the quests send you out into Gransys to kill newly spawned BBI monsters, so its fun and a nice change of pace