Then there's the question where Germany can expand peacefully at all. Spawn in Vienna, Frankfurt flips ... anything else can already get difficult with Warszawa's and Viking Denmark's cultural pressure on the borders.
If we had a bigger map, I'd gladly include it, but here ...![]()
Peaceful expansion is overrated

I'd be fine with it if independent cities are autorazed upon conquest. That helps create the illusion the map is bigger than it is by giving us more freedom as to what cities we would like to build there. Also we wouldn't be stuck with the same cities in the region for all games. If its still too crowded, maybe one well placed city could do the trick instead of two?
I feel like this does bring up the question whether we really need to separate the current HRE/Germany into two civs or not, especially given how crowdedness. With >10 civs in Europe alone from the Middle Ages on (France, Spain, HRE/Germany, England, Netherlands, Portugal, Scandinavia, Russia, Turkey, Leoreths awesome new inclusion of Italy, Turkey and possibly Greece and Rome), I think theres enough civs to work with to replicate Europes complicated historical conflicts and make for interesting gameplay.
I like the current idea of having one civ represent the German-culture historic powers and their successor states. What about using dynamic civ naming and capital switching to allow for the current German civ to better represent the HRE and Austria (capital at Wien) and later Prussia and Germany (capital moved to Berlin). Of course, Berlin would need to be made into a much more attractive place for human and AI players to build a city there.
If youre worried about human players aiming for their UHV goals too early, why not a combination of
-Up until year 1600AD, nerf military unit production when a human player controls the HRE/Germany.
-Up until year 1800AD, make HRE/Germany hard to keep stable and suffer severe penalties if they occupy foreign lands
-giving the HRE/Germany an addition Medieval Age UHV that will keep players busy for earlier parts of the game
-make the Vikings and Turks greater military threats, make Italy more of a nuisance. Add either one or two independent cities in Eastern Europe to be a military nuisance as well.