If you get a wolf hide for every wolf, a spider egg for each spider and so on, this could be the basis for many quests. Or you could just sell them in the cities. After you sell 10 wolf hides to a store some new clothing could emerge for sale. Even better if its troll hides
I think this kind of solution is the best, for many reasons:
1st: Why do society acumulates any kind of money? It's a measure of your possessions and the value of your work, that you trade for stuff that you don't have, so the society gets balanced: people work to offer a service and in return they get something so they can enjoy the services of others as well. Why would monsters acumulate gold, if they are not organized in any kind of society? What's the point for them? Specially in the world of Elemental, where the most inteligent races are just restarting the civilization almost from scratch. So it's valid to assume that if the most inteligent races are just starting to rebuild the world, the lesser races would have absolutely no society at all, and if no society, no reason to carry heavy stuff like piles of gold.
2nd: One wisely told this already: it's ridiculous that you kill some wolves and gain more money than a GOLD MINE CAN PRODUCE IN SEVERAL TURNS (witch can represent a month? a week? whatever).
3rd: You don't have to bury the idea of killing wandering monsters being lucrative, you just have to admit that they way you can do it need to change. Some people are arguing that in the late game armies cost a fortune cos they need the best items that are expensive. So what if those awesome monsters with 100 in atack droped the weapon they carry that makes them have 100 atack, instead of money? So you can equip your late game army with a late game equipament in a more logical way? Is that a new idea? Everyone that plays any RPG knows that it is exactly how it works. You bust your ass to kill the powerful guys not for money, but for the rare equipament that makes them powerful. And in case of monsters that have "natural weapons", they can provide other valuable stuff that can perharps create items otherwise unavailable: killed a mighty dragon? Then get his claws, or teeth, and make a rare sword with it. Get his scales and make an armor with elemental resistances. Killed wolves? Get enough hides and recruit troops with leather armor for a cheaper price. Killed trolls? Get their blood in vials and make rare potions of regeneration in the next city that has the apropriate building. There are many things that can be done, much more interesting things than just give you gold, that will add to the game's lore and experience greatly.
4th: Since the pursuit of quests can also be a winning option, to focus in monster hunting should remain a viable way to keep your empire going somehow.
Well, there is a lot more that can be added, but I think this 4 arguments are the most basic and stronger ones to justify an overhaul on the monster loot system.
Cheers everyone.