a lot of todays programs administer extended data for places, but in different ways. webtrees should be able to import and use these data via gedcom. The aim should be to be able to submit descriptions, pictures, coordinates once for a place and have it available on every event connected to this place.
It should also be possible to take name changes and administrative changes (county, parish) into account. A very good example of such a place hierarchy is
gov.genealogy.net/Locale.do?language=en&country=uk