Roddenberry wanted the political equivalency of two strong powers opposed.

This wasn't unique to the Cold War era. Before that we had France vs. Britain; Spain vs. France; Catholics vs. Protestants; Christians vs. Turks; Rome vs. Persia; Sparta vs. Athens.

Roddenberry wasn't making actual parallels about the economic or internal policies of the Federation vs. the Klingons, and that's one reason that his concepts have stood up so well over time. It took a succession of morons oversaturating us, ruining the optimistic core, and engaging in brand damage to loses us. Even now I bet if they'd come out with a decent take we'd cautiously over time return, and it's thanks to the original vision.