Mr. K makes a pretty interesting point about all that... Perhaps make your map of medieval Germania... Hmm... Yes..... lol
Your river system is ridiculous for one reason: In-continent attack/fortification. If you're trying to take North Germany, you've gotta go from Brandenburg through Dresden, and into South Poland. Or assume you've got to make a run through West Germany (good luck)... You have to go through the Alps to take Die Elbe, and you'd have to go through TWO countries in Belgium to take Bremen, at which point you'd better be playing unlimited fortification or have a lot of troops left over, because there's no way to fortify there.
Speaking of rivers, how badly is it gonna suck when you attack Rothenburg from Tubingen and you've only taken half the country because of the fact your guys can't cross that damn river?!?!



