I feel that in order to fill out the map to include all of Europe, current DLCs will need updating because if you look at the Going North DLC, it misses out huge chunks of Norway and Sweden. Whether Western Russia is included is another question, although some area of Russia will be included with the upcoming DLC (Beyond the Baltic sea). It's a huge task and begs to ask whether the community would rather have more simulation features in the future or a team more dedicated to filling out the map. Much like the current state of Germany in 1.31, the older map sections will need updating. If the whole of the vanilla map is to be updated, there will be a significant delay to adding new areas. In my opinion, it's probably best to go with a third-party map mod such as promods if you crave a larger map for the moment. To answer the OPs question; I feel that all the countries of Europe will be added eventually, just not necessarily the entire area of each country added.