I know what you're saying and i dont really want to sound callous, but to me hitler was a man of the people, reflecting the general hate and bitterness of Germany. His passion won support. Hitler's motivation for war was living space for the German people, which he believed were great, and they blushed and believed him.
But stalin was this shadowy figure who emerged out of obscurity to realise he has absolute power thru the hard work of genuine revolutionaries believing in something better. Stalin left it to others to build a god-like image of himself, while he was really a "rude and evil man" as churchill put it. He worked thru the night scribbling figures in the thousands on the margins of lists of people who were to be killed, or specifying that ONE person be taken out of thie list, just to give him a sence of power. He wasn't a smart guy, an educated guy or a popular guy. He was sadistic to the extreme and decented into a depraved type of madness.
Stalin had NO mativation, killing people for NO political or strategic purpose. Too me, that is pure evil...innocent people being sent to their death or work camps. Not to mention the cold statistics that put Stalins genocide in a much higher catagory.
Plus, if Hitler had won the war early on, maybe we wouldn't have the a-bomb...a fact that has raised the stakes of any state activity.