If they hadn't attacked the USSR:
The size of the german army on the western front would have been four times greater. And the crucial allied air superiority would never have been achieved.
So you would have had somewhat equal forces.
But then again, according to Discovery Civilization Channel:
The fact remained that in all the aspects of war, the germans were superior.
- They had far more advanced technology, and much more reliable weapons.
- Their tactics were superior on all levels, and german officers were trained to use their resources to 100% efficiency(something allied officers were incapable of).
- Their soldiers were better trained, better lead, and were often more willing to die for their cause. Whereas among the allies, only the Russians showed the same determination to fight to the death.
In fact, allied generals had given full consideration to this matter, and came to the conclusion that if they met the germans in anything close to equal numbers, the germans would win.
So the outcome would have been a german total victory.
So what would the world have been like? You would have had genocide of half of the people deemed subhuman by the nazis, and the world would be packed full of germans. Evil? Not really, not if you consider that it isn't evil how the Anglo Saxons genocided the native americans, native canadians, australian aboriginals, native new zealanders, and many more, and then settled in their place.
