There are a lot of SOVIETS and a good number of Russians in Central Asia. Those in Central Asia would be beyond the goals that Hitler had set out, and most of the people in the 'Stans were not Slavs. Slavs in European Russia would be in a world of hurt. If 50% were alive 20 years after the Reich won it would be surprising.
It isn't hard to isolate and eliminate populations, especially in the Russian winter. Take away the fuel and food in October, do a bit of burning and by April you will have thinned the population quite nicely. As a "bonus" you will also have reduced the "unproductive" elements (children, the elderly, and women) in a higher proportion than those who can be most profitably worked to death.
What is often forgotten when discussing revolutions and partisan activity is that the effort requires support. Partisans without any base of support for weapons and some sort of leadership are little more than bandits. Partisans facing well led opponents with good supply, armor and air cover, will always lose. If the organized force has a totally unfettered ROE the Partisans will be obliterated, usually by eliminating the civilian population that supports it.
It is important to remember that the Nazis were perfectly willing to kill EVERYONE in a community, just to make a point. We are not talking about U.S. or even Red Army forces which had limitations on what they were allowed to do. We are discussing forces where the COMMANDERS are encouraged to be exceptionally brutal. What would get you a noose or firing party in an Allied Army or a bullet behind the ear in the Red Army, would get you a decoration or promotion in the SS. The Party intended for ALL land forces to be Waffen SS once the war was over (can't really trust the Army, too many old fashioned ideas, like honor, ingrained there).
You repeat the barbarism of Lidice (and the lesser known, but even more brutal razing of Lezaky) 40 or 50 times and people stop being willing to do ANYTHING to help the partisans. Often they will begin to inform, especially if they are starving and informing means getting enough food to survive for a week longer.
The Nazi religion was Nazism. You have to take a lot of the stuff on the Military Channel, especially the sensational stuff, with a whole shaker of salt. I usually recommend having several throw pillows at hand so you don't damage the TV when frustration over the stupid oozing out overwhelms you.
Ah, a discussion.
I have no doubt the Nazi government would LIKE to genocide Russia, but I simply don't see it practically happening, as there are (cough) quite a lot of Russians. It could still be done, but unless Germany is really good at isolating different areas, I would imagine a huge revolution, that would sap Germany's strength considerably. It'd be a massive insurgency.
Here's a fourth question. ASSUMING Hitler's supposed occult religion existed (such as seen in that one Military Channel documentary, Nazis: The Occult Conspiracy), is there as snowball's chance in hell of it actually being adopted by the German people? It's certainly possible for people to convert on such a large scale.
As an American, the depiction of Russia as a new frontier for Germany interests me... a pioneer culture. I'm pretty sure the German state would manufacture a baby boom, within a generation there would probably be many pioneers for a Lebensraumed Russia.
EDIT: BTW, what I'VE read about German views of the US were that they considered British and Americans both to be estranged brothers... not Germans, no, but closer to them than other races. Of course, America is also a mutt.