If I may shamelessly ship my own maps, I am particularly proud of my dolomites map (the first version got included in the officials, but I made an updated version later)
Does something prevent the updated version from becoming the official one?
The only reason I can think of is that it might take the savegame compatibility away, my guess it that even that would not happen. If the new version is an improvement, then it would be a disfavor not to upgrade the official Dolomites. Maybe you should open a ticket at launchpad?
The way that we added new maps/updated maps for Build 19 was that some people got together and curated them. It makes sense to do this on the forum. so we can get the people who know the maps best involved in this.