Surely these factions need things other than errands and manpower to function, right? Some plants for the avakots of Alca's Children? Metals for the weapons among the Kith of Kings? Maybe even some cloth or other crafting goods for the agents of the Silent Rose?
Might not be the most efficient means of getting standing (nor should it be), but I'm sure it would be a welcome alternative for players wanting to explore the world and not have to think about the non-stop Sparrow Tales grind.