I'd like to see supply chains. Perhaps food is a nigh mandatory buff, so a settlement worth its salt would want to provide access to food, which could require sums of meat and wood for players wanting to build it up to gather. Perhaps metal and leather brought back could be used to make equipment which not only goes towards arming players, but maybe funding NPC guards to keep it safer overall. Little things like that could make it very easy to set goals for contribution when hopping on for a bit, or give cause for resources to be fought over besides simple expansion.
