It is not just merchant wards that are in need of a mini-map. Almost all the instanced storyline quests in non mainstream areas have no map. The supply rooms of the goldsmith guild, the hospital wards of the alchemist guild, the inn at the adventure's guild in Gridania all have some decently sized areas with no map to help navigate. I was surprised though that the special island for the blacksmith/armorer final quest did have a map but the island was pretty plain besides a lighthouse and some underground tunnels which never are displayed on a mini-map.