Reinhardt Heydrich, probably the second most feared man in the 3rd Reich, what if this cold, ruthless monster was never assinated. I know that he was attemting to harness the resources of the captured territories to enable the war on the eastern front to be fought more efficiently, what impact would his contribution have made ?

If Heydrich survived I daresay the reprisals would have been much more terrible on his orders.

Had Heydrich been successful, and raised the 'efficiency' of the German pillaging of the occupied territories (a pretty bloody ruthless exercise anyway), then I think the effect would not have been war-winning, but would probably have dragged the war out longer (possibly very considerably longer), especially given Speer's reforms of the economy from 1942.