It would look like a sign of weakness,I think. Right after being stopped at Stalingrad,all of a sudden Hitler "turns nice." The extra manpower and transportation would be beneficial. They wold lose the forced/slave labour. Stalin had 10s of thousands of civilians to dig the defences at Kusrsk for instance. Who would help Hitler build the Atlantic wall? I would'nt think he'd inconvience the German population by getting them to do it.

As mentioned, Germany would have looked better as Liberators but I don't know how he'd look doing a 180 turn-around. From killing Jews to just stopping. Maybe[?]
the Allies would'nt have wanted un-condtional surrender?