I agree about Breslau being a rough hex was a wrong thing. Also, it was really not accurate not to include any forest areas in Poland, East Prussia, Silesia and East Pomerania so it was clear all the way from USSR borders to Berlin. So keeping in mind this I have edited all the possible map changes in Poland:
F is for Forest hex
C is for Clear hex
I have checked that all german hexes close to Oder river should not be rough hexes but forests hexes or, in case of Breslau city, a clear hex. So Breslau will be in a clear hex. All Borger´s points in the post above about possible new forest hexes and excessive swamp hexes around Brest-Litovsk were correct. To these ones I have added some other based on the actual map. To mention that East Prussia has a significant forest area in the south, shared with Poland and the most important, NOT ALL Pripet marshes region should be considered as a never ending swamp zone since there are many forest areas between and, on the other hand, many hexes should be considered as clear hexes.
Finally, two changes regarding cities: Lvov should be situated 1 hex NW (also checked) and the possibility of including the strategical city of Kolberg in East Pomerania with a sea port.