Right now, the main use for gold is upgrading units. Yes, you can also trade with gold and speed up production but at least I did never tone down research just to do that. So here's an idea for another use of gold: Mercenaries. Yes, I know there's already the Guild of Nine. But that's the only kind of mercenary and it's a rather cheap way of getting them. How about neutral mercenary camps you can randomly find in the world - you have to visit them directly with a unit to enter them. Each time you enter them, you get an event in which you can choose to buy the offered unit or not. The camps could be used by every civilization, all the time. There would be different types of camps and each one of them would sell different kinds of units, like: Slavers - Sell slaves of various races. Beast tamers - Sell tamed animals. Bandit camps - Bandits offer to fight for you but they can be unreliable. Necromancer camps - Sell their undead creations to you. To balance things, the mercenaries have a much higher maintenance cost than your units and cost a rather large amount of gold. Slaves already work much slower than normal workers afaik. And finally, there could also be "bad" events. There could be no available mercenaries at the time you visit. Or you could get scammed, like you paid a lot of gold for a very strong unit but get a useless, withered unit instead. And you'd have to tone down researching to buy those units, so I think that would be a fair trade-off.