Before any other book I would like to see development of the rest of Golarion.
Arcadia, Azlant, Casmaron, The Crown of the World, Garund, Sarusan, Tian Xia.
We don't need a new world, just finish what you have now.
THen you could do settings for Aballon, Castrovel, Akiton, Verces, The Diaspora, Eox, Triaxus, Liavara, Bretheda, Apostae, and Aucturn.
Or just make each one like a map foilo pack. The map, and then maybe 20 pages of info and leave it at that.
Not once in any D&D setting has a full world been developed, not sure if Mystra was fully developed. So I may be wrong.
Any how. Finish the world, and solar system before creating a new one.
