Apparently someone has to say a few things out loud here.
1) During the development of CK2, the developers voiced their idea of turning the terrain mapmode into a useful one so that players would spend most of their games in it, only looking at the other modes for specific information.
2) In CK2, if the fort* of the province is occupied by a force different from the owner of the province, then the colors of the occupier appear striped over the province, even in terrain mapmode. Furthermore, countries* you are at war with have a pulsating red frame along their borders. (*: I used the term approppriate for EU, not for CK)
Thus they did a really good job of integrating the meaningful information of the political mode into the better-looking terrain mode.
3) Such 'secondary striped over the primary' approach - already present in political, cultural and religious mapmodes in multiple games - could be extended to include more information about minorities by adding a 'tertiary' level. To take it from the EU3 system, the primary would cover 2/3 width and full height of the 'tiles' of the map, the secondary cover 1/3 the width and not the full height as it does now, but only about 2/3; the tertiary thus having left 1/3 of both directions.
4) Just to state the obvious, until Paradox games use different maps, conversion is a really hard job.
For this and other reasons, I don't understand why Paradox doesn't commit itself to a strategy of creating a string of games - CK2+, EU4, V3 and possibly HoI4 - that would use the exact same map (with approx. 50% more provinces than EU3) thus allowing for a relatively simpler but more accurate converter to be made. Furthermore, making such a map would be a more efficient policy, since it would have to be created only once, not 3-4 times over and over. (An obvious requirement would be to have the games slightly overlap, currently there is a 20-some years gap between EU3 and V2, and about half a century missing between EU4 and V2.)
Alternatively, knowing the high number of provinces a HoI requires, make CK2+, EU4 and V3 have the same maps, and call them the low-level regions of HoI4, harboring multiple provinces, with CK-EU-V regions called high-level regions.
