Is this my nerdiest post? Yes. Anyway,
The Star Trek wiki had something interesting...
Paul Schneider modeled the Romulans on the ancient Romans, naming the species' homeworlds after the mythical founders of Rome, Romulus and Remus. "It was a matter of developing a good Romanesque set of admirable antagonists that were worthy of Kirk," Schneider related. "I came up with the concept of the Romulans which was an extension of the Roman civilization to the point of space travel, and it turned out quite well." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 34) D.C. Fontana reckoned that Schneider basing the aliens on the pre-existing Roman civilization was the cause for the writer receiving insufficient credit for creating the Romulans. ("Balance of Terror" Starfleet Access, TOS Season 1 Blu-ray) Gene Roddenberry, interested in ancient Rome himself, approved of the initial depiction of the Romulan species. "He loved Paul's having endowed the enemy-Romulans with the militaristic character of the ancient Romans," wrote John D.F. Black and Mary Black. (Star Trek: The Magazine Volume 2, Issue 11, p. 19) Roddenberry's original concept of the Romulans, however, was that they represented 1960s' Chinese Communists.
Yes, Romulans are somewhat based on the Roman Empire and are xenophobic conquerers, but Westerners often ignorantly attribute these traits to communist countries anyway.
Then there is the Klingons, again, the Klingons are nothing like communists, (they're a patriarchal empire) and yet I've seen people say they were based on the Soviets.
So what do you think?
It's too all over the place to many any one particular thing. I remember one episode where they being back a ancient klingon and he is just a rad punk/heavy metal biker kinda guy. He throes shade at all the other klingons for being too much about honor and not partying. That would be a good direction for a space warrior race that could use a replicator to fix broken bones instantly you know? Plus Gene Roddenberry would have liked the excuse to get more weird fuckin' in the show. Like all the Sci fi writers of the time he was hornt more than you can imagine. I am pretty sure that is how he got Into Hollywood.
I think you're combining 2 episodes. They cline Kahless the ancient Klingon dude in a tng episode and Worf gets berated by normal klingons for not being a biker punk party guy. Worf was raised on earth and only understands klingons from the outside but desperately wants yo live up to the image where they klingons in the empire know a lot of the philosophy and stuff is practiced seriously. He's like a weeb for klingons.