I have an idea.
How about at the end of the war, a B-29 flys over the losing countrys' capitols, and drops an atom bomb.
It will be in the game, just not player-used. Kind of like the 105mm AA guns at the strats.
As for the Friz-x, it would be a decent trade off. You get an almost guaranteed hit, but you do less damage.
However, I could see it being abused as a Tiger II buster, which should not be allowed under any circumstances; its not an 'effing anti-tank missle.