Give us ideas if you have some
Trade Routes [Contingent on the existing roads/ports, modified for war (Sacking, banditry, piracy etc.) with certain powers being able to interfere on such a level], Religous fervor [Moral authority of the church allowing for such things as those occurring in the latest book. Mostly, I would like to see the High Septon do something.], Relics of Old Valayria [Artifacts, swords, etc. getting introduced that provide some minor stat bonus and are inheritable or steal-able; only available by special event or an expedition], The Others [Coldhands grows restless...], ability to hire foreign experts [By event, gain foreign courtiers], bodyguards [Employable protection by courtier, maybe granted by title? Protection in combat, assassination, etc. Negative relations or plot could have them kill you.]
I'll expand if requested. Just bouncing some ideas around.