I though my region list box handles Duchies pretty well, though yes it has issues with realms named after the capital. I haven't really looked at how to handle imperial regions though. The bigger problem for me about rolling the thing out is that semantic data still isn't updated without a page save. One way around it that might not be as big a resource drain as the standard semantic update script, would be to produce a couple of pages that import all the external data about regions etc, and then have a script update these pages at whatever interval.
The need to save a page to refresh the semantic data is unfortunate, but can be worked around. I run an admin script on the wiki every other day or so that refreshes the semantic data. This means that the semantic data could be as much as two days old. While that is not ideal, it means that pages that use semantic lists will be updated on a regular basis without manual intervention.
I don't think the idea of one big page with all the external semantic data would work at all. The context of what page the data appears on is an inherent property of the data. If you created a page [[ImportOne]], there would be no way on that page to say that [[Brive]] is part of [[Perdan]].
If you look at the Arcaean region pages, you can see Part of is already holding multiple entries, so I'm not 100% on what the advantage of moving to record type property, unless this type would make it easier to figure out which on the entries is associated with a level of realm hierarchy?
The idea is to specify what that region is a part of. For example, right now on EI, Fontan city is not part of the realm of Fontan, it's part of Sirion. So if you put [[part of ::Fontan]] on a region page, are you saying that it's part of the realm of Fontan or the duchy of Fontan? And if you want to see what regions are in the duchy of Fontan, you'll actually get a list of all the regions that are also in the realm of Fontan.
The idea of the Record property is to add context to the the "part of", while still allowing us to resort to having a separate "duchy of" propertry. It would denote what that relationship is: region>realm or region>duchy.
