Well WW3's death toll evidently wasn't all that high, all things considered. Given a population in the 10 billion range, 4-500 million while still a tragedy of unfathomable proportions, would mean a fair portion of humanity got off scot free. Presumably most of the casualties would have been in the combatant nations, which would mean you'd see enormous death and destruction in a small portion of the globe.
Do kinda think this and the Eugenics War are a missed opportunity for movie storytellers. I mean the Khan revelation in STID would've been meatier if there'd been like a Cumberbatch centered EW/WW3 movie as a prequel.