I got an idea that can make this game more exciting and challenging for players, who lack certain global resources in their domain. In some cases, like researching sulfur, this lack means blocking certain buildings without having the means to replace them with better alternatives.
Seeing a lot of blank cells, sofar sometimes used by players to build new towns, I think most players would like an alternative use for them. If it would be possible to develop those cells to spots with global resources, this new aspect of the game would give players more means to develop their domain and to keep on researching and progressing.
There can be many ways to allow this possibility and I'm sure it will not be easy to find a good balance to the existing balance of global resources. But I see a lot of benefits to the game in general, like an extra motivation for PVP interaction (stealing what others have unlocked; persisting development instead of losing interest; specialisation of domains towards naval/trade/offensive/defensive etc.)
ROUGH OUTLINE:
- New troops (discoverers) besides explorers for each age, that have a certain base chance (e.g.1%) and max size (e.g. 10 units) to discover a new global resource in a blank cell for that age (e.g. miners, farmers, biologists for mine/plantation/pasture). Maybe add a bonus or limitation by perks (e.g. base chance +X%, max troops +Y). Sending more troops of the same kind gives an accumulation of base chance.
-Limited attempts per blank cell (e.g. 1 base attempt and perhaps additional attempts by perks). This will make players think twice to try to discover a global resource in a blank cell. Also because a hidden global resource will be destroyed and replaced by a lesser global resource in most cases.
Maybe you like it, maybe you don't. I could overlook pitfalls or be too much optimistic. Whatever the case, I think it's an idea worth being discussed from any point of view you can think off.