[Dimaz]

Yesterday when I was going to sleep I was thinking about how to deal with gemgens (if I had the code access) in some more or less balanced and flavored way. So these ideas can be considered as produced by half-asleep mind, but still...
Clams - they are supposed to concentrate astral magic from environment and solidify it as pearls, so they can be connected with the amount of magic gained from other sources (showed in the graphs). Something like Nexus, but connected to one nation. So you can get maximum of your pearl income + 1/2 of other gems income divided by some coefficient (4?), and if you have more clams they have no environment magic to grow the pearls, so they will either stop working at all or give you pearl with 10% probability. So for example with income of 20 gems of each kind (140 total on the graphs), you'll have max 20 clams working - big number, but not insane. As I understand another problem with clams was that they lead to turtling for nations that can forge them efficiently - and when your clam income becomes connected with "real" income, it becomes less of a problem.
Bloodstones - they seem to be connected with "earth blood" and the earth that constantly bleeds becomes dead sooner or later. So concentrating large amounts of them can reduce resources and/or supplies for the nation. Like, every BS subtracts 5 resources from each province of the owner. This way the ability to build units and later even mages becomes reverse proportional to the number of stones, so sooner or later you'll have to stop producing them (this will also give more importance to production scale). The only exception that I see is LA Ermor but he has problems with blood slaves so probably it won't give him big advantage.
Fetishes - they can start spreading desease when there are many of them collected in one place. So for example if you have more than 5 fetishes in the province they start to act as bane venom charm. This will increase MM however so probably there are more elegant solutions.
WL, I will join such a game if I'll still play Dom3 at the time (currently I'm a bit tired of it so maybe I'll take a break after my games are ended).