God knows what would happened if they had managed to occupy Russia!
Besides, war is all about fame and glory.
Excusing the Russians' war atrocities simply because they beat the Germans is quite like picking the frying pan instead of the fire - they are both very bad, just one is somewhat worse than the other. (Then again, I'm from the Baltic states, where we were actually stuck with the Russians until 1990, so I am probably biased.)
Did the Nazis have long distance bombers that could actually destroy the industrial complexes in Ural or further to the East? I am not aware of any.