I tried searching "world map", I'm sure it has come up before but trying to search this is useless due to how often the term map comes up.
Whenever we start next world, I think there should be a world map created along with terrain generation. The reality is, world maps have been integral to the haven community for a long time. They aid in gameplay choices (I heard murder city is in the south, lets settle south east just to be safe!), they aid in road construction, they're pretty important for long quest navigation, the list goes on.
I don't think it's necessary that the map be updated after world launch. Reality is, town location other than big factions isn't a critical detail. And rather than updating the terrain (a hideously expensive process to maintain I'd guess) it would be an awesome thing to have realm claims marked on the map instead. This serves the function of indicating faction presence, without the messy business of tile updates. Also having an official map makes the resource more accessible to beginners since a static link could be incorporated into vanilla and custom clients.
Overall, adding a one time processing cost to server start and the minor processing requirements required to update realms (could even be done just once a week if it happened to be an issue, but would maintain relevance) seems like a worthwhile cost. I'm not sure what hosting options are available, or what the cost increase would be on that side of things though.