If he dies very early on, say still in '33, than that means a really different future for the Nazi party - as the SA still exist. If it is somewhen later on, but still before the war, I see the Nazi Party staying in power but WW2 either not starting, or being very different. Anyway, it would probably mean a smarter Fuhrer. If it happens during the war -especially during the later stages of the war - than I see a struggle for power between the different factions in Nazi Germany (with the SS trying to seize power). The Nazi regime was highly disorganized and chaotic, because if it wasn't than it meant he could simply be replaced for everything to simply go on. He created a chaotic system so that it relied completely on him, and thus if you remove Hitler, the system would collapse as it is not clear to whom power goes - Goering? Goebbles? Himmler? All of them are power-hungry and would likely try to seize power when they can (and, IOTL, two of them did try to seize power for themselves when it became clear the Fuhrer was no longer functioning). There might be a Nazi civil war (though I cannot tell where the Wehrmacht would stand in this - would they try to oust the Nazis? would they wholly support one side over the other? would some generals support different factions, so it will not just be a Nazi but a German civil war?