In previous installments, gold seemed to be worth more than it does in civ 6. The only major shift in its use between 5 and 6 is the ability to purchase the loyalty of city states. Adding this feature can allow a civilization to focus entirely on economics, without having to pay much mind to building or maintaining a military,whilst also ensuring the protection of their cities, so long as they keep there citys near friendly city states. This would add a ton of cool game-play mechanics where civs can steal city states and pul the rug out from under economic civs, or allow a rich civ to attempt to monopolize the unique bonuses the CS can grant. it would be neat to have some sort of mechanic that alters the price or frequency of a buy with a government district, and have the price go up exponentially throughout the course of the game. its just that a purely economic civ doesn't seem to viable at the moment, in the way that a civ like Venice did in 5. On top of that it would complement the addition of a world congress, which i think almost every one wants to come to civ 6.