So, if there were region labels, how would they differ from country labels?
Different color?
Yes different color. Maybe also different zoom level (but this is not so important).
As I mentioned above, the most flexible would be:
It would be even better if we could set extra labels anywhere on the globe for naming geological formations or anything else.
For example one could put labels with "Himalaya or Shieldwall" on a rock formation or "Eternal Wastes" on ice formations.
Code could look like:
globeLabels:
-[x-coordinate, y-coordinate, "label-text", font color, zoomlevel]
Labels won't do you much good since there is no way of telling where are its' borders. Using countries as regions makes more sense on a custom planet IMO...
I may use polylines for the borders. Polylines are independet of country and region definitions.
Using countries as regions is not so easy, since alien missions are defined only by regions and the regions also appear in the graph screen.