Responded to your PM, Naeg.
I managed to make Ghostblade and Drainheart effective without any sort of loop or glitch. 5/5 Armsman makes them deal double damage, 2/2 Dual Flurry makes them have a much higher DPS, and Dual Savagery does even more damage. So you have double damage, 35% faster DPS, and dual wielding attacks do 50% more damage, resulting in them being very effective in difficulties even above adept.
Responded to your PM, Naeg.
I managed to make Ghostblade and Drainheart effective without any sort of loop or glitch. 5/5 Armsman makes them deal double damage, 2/2 Dual Flurry makes them have a much higher DPS, and Dual Savagery does even more damage. So you have double damage, 35% faster DPS, and dual wielding attacks do 50% more damage, resulting in them being very effective in difficulties even above adept.