It's a consequence of their geography. The islands are poor, and have nasty travel times. This leads to a weak realm. Shady has the right idea in mind: Expand to the mainland. That means going after the Sultanate. But the problem there is they have to land on the shore right next to SoA's capital... Their only other alternative is to become muscle for SoA or Perdan, and devote themselves to long marches to fight battles.
