Immense resources for spending
I'd like to see the devs add the ability to either use immense amounts of resources to purchase sketches and medals...or sapphires (since both can bought with them) at the black market under a separate tab.
It could be set so that ONLY resources gained from resource production, raiding, or tournament rewards could be used.
Perhaps a new 'savings' building that a player could transfer resources to, but the resources could only be used to purchase the currency (whatever the currency the devs were willing to allow). World Wonder projects from Civilization games comes to mind here.
If not a building, then perhaps something similar.
When I mean immense, I'm talking tens of millions, or hundreds of millions. I suppose instead of a black market tab, an actual building, such as an altar, could be provided in game. Once the player has transferred enough resources to the their 'savings', the player converts 100 million gold, iron, and food for a specific amount of sketches or medals or soulstones or sapphires. Perhaps an altar for each or just one for sapphires.
I'm just trying to convey an idea that would allow those who were willing to spend the time and effort to have a way of maximizing buildings and troops, gaining various black market items, or whatever they feel is important to them, without having to spend actual money. The method of doing this could be something completely different.
The time and effort needed should keep the coiners who have more money than time spending. Plus, player activity would increase as time and effort would mean something, allowing players with more time than money to obtain items previously out of reach, which would then give more players for the coiners to interact with...in whatever fashion suits their diplomatic fancy.