Actually SeaMonkey you have been around long enough to know I am a big proponent of various possibilities, the big push for increased flexibility with diplomacy probably came from me, at least I remember in SC2:Blitzkrieg beta testing continually being the biggest poster (Hubert might say "spammer", hehe) in the beta forums for more options with diplomacy and possibilities ON the board when you do DoW.
I just want it to make historical sense and not totally go into the virtually impossible and my opinion is that peace with Germany was not possible unless it was late 1945 and Germany still held on in some way and asked for an armistice.
To be precise, my opinion of holding on means the following in SC2 terms:
Major Axis Victory for Germany = the following parts still in German hands by December 1945:
Germany is secure (includes Poland), Italy has Rome plus 2 other cities.
Minor Axis Victory: Germany is still alive (includes Poland).
Or the idea that Germany could obtain a nuclear bomb... simply not possible, remember that to this day it is still the most expensive scientific project ever undertaken. Germany was nowhere near having the resources to do what USA did. Ok so not impossible but if the Axis invested in nuclear tech (if it existed) then it would pretty much sink its economy in it and put all its eggs in one basket "hoping" it would be enough to stop the Allies and negotiate peace.
The project also displays USA's economic might, they were severely outproducing the Axis (combined!) by 1941 and they were putting billions in that project. The idea that the Axis could somehow DEFEAT the Allies when they are being outproduced in all areas by everyone as early as 1941 is simply not looking at it from a sheer numbers perspective and I do not believe that having the better commanders (still debatable) would have made a difference because the Allies would have needed to be total idiots to screw up their humongous advantage.