Drop rates on the drake parts are imo ridiculous. A guildie and myself have cleared west and north tov's trash mobs roughly 10 or more times in the last three days (I'm working through it now again myself) and neither have seen a drake kidney which we both need to finish.
I understand the idea of random drops and how its possible for this to happen, the point is that there's no reason for the drop rate to be so low. For Charm 3.0 you kill the royals in Chardok and each royal is guaranteed to drop two heads. Mobs in the epic weapons quests all drop multiple quest pieces every time etc.
The quest could be improved by simply taking each of the four drake colors in tov (red, black, blue, green) and give them an amplified chance maybe 50% to drop a certain part and no others, then make the glimmerings have the same rate but drop from the pool of four parts and remove the drops from the wyverns and wurms since after all, they're drake parts for a drake essence.
I haven't started in on the ST phase yet, but I imagine the drop situation is the same and if so I would recommend that be addressed accordingly as well.
As I understand it, the quest is intended to increase the strength of the charm as the character increases in strength and progression rather than the ability to farm drops.