Hello,
Did you ever think about adding new Quests for the "useless" jobcave mobs? Like the Bowman in that room between Kepris and Sandman or the Sopdu?
Regarding the current situation with coins it might be interesting to add one quest to Bowman for silver and one to Sopdu for Copper Coins. Same as the SP quests: 1x per day.
Wether you should get 5 coins or just 1 is a balance issue I dont want to adress...
That said, you could improve the situation with a less abuseable method by just cutting the coin prices in half for all upcoming releases or at least reduce them a lot.
My suggestion would be legs/earrings = 80% of chest price, head 60% and right side/rings 50%