I think a general outline or sketch or something like that would help a lot.
If you are developing an RPG line there must be some things buzzing around in your mind.
Even something as vague as "Some Kingdom here that does this and some Kingdom there that does it the other way" would help a lot.
Maybe a rough pencil sketch? Or a description?
It's a lot easier to suggest changes to an existing outline than not knowing what you are looking for at all.

Just my 2 cents.