Ideally, a rework that improves drop tables without just introducing a massive amount of gold would be great. I.E, no gigantic stacks of rune armor. But then again, with the general store it's sort of impossible to introduce such a rework without furthering inflation of the economy.
I would propose 'tiered' drop tables. Low level monsters drop low level skill materials, mid leveled drops mid level, etc.
Low level bosses could drop larger amounts of mid level resources, with other bosses dropping larg (But not too large) of high level resources, with highest level bosses dropping the best materials, in lower but consistent amounts.
Examples of low, med, and high resources
Seeds:
L: Potato, Marigold seeds
M: Irit seeds, Willow seeds
H: Torstol, Yew seeds
Bars:
L: Iron
M: Mithril
H: Adamant