Factions could have one or two preferred settlements that when turned into an outpost give some sort of bonus to the troops stationed there. I have been playing the Libertatia faction and was thinking that i would be neat if they had a prefred settlement like the castle or the lighthouse or spectacle island, Minute Men could get a bonus from The Castle or Bunker Hill, BoS the Airport, Institute could prefer covenant or somesuch. Would work well if the npc factions could take settlements, and have a preference for capturing certain ones.