I've been playing around in the editor trying to figure out what everything does and stuff, and I've added a couple more resources, like horses, mana crystals, warpstone, potions, saltpeter and graveyards
because I felt like all races could build plenty of stuff but nothing really depended on resources (except for the nodes), so now if the unit rides a horse it needs horses, if it's a humongous demon it needs warpstone, if it knows magic it either needs potions or manacrystals, iron for the iron heavy ships like the fire ship and for cannons, heavy units etc, also saltpeter for cannons and the likes, imo it plays more strategically because now you really need to hunt for resources more, especially if you are undead then you need graveyards for almost every produced unit
most resources become available after some research, like horses after nature III, warpstone after chaos III and so on
I also changed mithril into a strategic resource, now angels need it to be built and other high end units
I hope you don't mind me changing your mod like this, but I just wanted to tell you what I had done, maybe you had some similar ideas but then dismissed them in an earlier version.