I'm confused on a few points, but I think most of them are just due to it being a bit of a WIP still.
Many of the skills etc. aren't clear yet. As an example, the

skill tree says they can build windmills on plains spaces, but it doesn't seem to say anywhere what a windmill does.
Similarly, it says that the rare/non-rare cards are different, but it doesn't explicitly say which ones are rare (some of this can be inferred from the craft skills).
Are there other ways to gain XP from those listed? (quest rewards etc)
What do the different types of terrain do?
Who controls NPCs? Is it the moderators or people from that element?
When trying to declare peace, what happens if there is a single player who keeps attacking the other element, or something similar? Is there any way an element can "exile" a troublesome player?