So the main problem is not the rate of drops for fragments/key mats recipes but its the variety.
Current drops in party zone :
10 weapons + weapon recipe s grade
robe S grade - helm main gloves boots
heavy S grade - helm upper lower , boots gloves, shield
light S grade - helm , main boots gloves
+ armor recipe s grade
dc robe - helm main boots gloves
talum h - helm main boots gloves
majestic L helm main boots gloves
+armor recipe a grade
That is total of 40++ possible drops , there is good chance i missed some or added some extra but still the variety is HUGE , and we all know which ones are most wanted for every single player with some exceptions
in my personal opinion we should separate A grade and S grade farming areas , put all A grade in solo zone and all S grade in party zone it should help with farm a lot.
dont really care for drop chance if its hard,easy or medium but just decrease variety of possible outcome by separating A grade from S grade .