Don't give in and censor the game. If Germans won't buy it because Hitler is there then don't sell it in Germany. Absurd law for an oversensitive group of people. They want to be super progressive and liberal and overwrite their past. Now they are suffering the consequences with the migrant crisis.
First, you can't assume that Germans won't buy it because there is a law which prohibits endorsement of Nazi ideology by showing of symbols associated with them. The law doesn't exist because Germans are oversensitive. It is a consequence from the events in the Nazi time. Depicting the associated symbols is therefore only allowed in special circumstances (movies showing the Nazi era, history education, etc.). The names are not censored.
Second, you can't assume a general consensus regarding what Germans want ("they want to be super progressive and liberal and overwrite their past"). There are various opinions on this matter. Some simply want to forget the entire thing while others say that we must never forget what happened to be able to prevent such things in the future. The Nazi time is part of German history, no doubt. But it is nothing you can be proud of.
Third, it is not a migrant crisis. People fleeing war and sudden death are refugees and not migrants. Furthermore the problem is not a progressive society. The problem (among other things) is the ignorance over the last years towards the events in the Syrian region and a catastrophic outer policy of many 'western' countries. The solution can't be to shutdown the borders and build walls but rather to take responsibility for the devastating effects the policy of the last years had.
I don't see a problem in having darkened faces for the major Nazi people and a different flag (which is also a historical flag) being used in the German censored version. That doesn't reduce my gaming experience. Quite the opposite, I don't want to see Hitlers face or the svastika every time I play. I've seen both on many occasions in movies, historical material, etc. There would be a problem if gameplay would be censored but that won't be the case for this game.