In fanfiction I tend to render the Romulans with three main aspects:
1) They are IMPERIAL AMERICA: They consider themselves a Democracy, the most-free and most-enlightened people in the universe, they believe themselves to be exceptional and the envy of the galaxy. They think everyone hates them out of jealousy, and consider themselves the rightful military and economic masters of this galaxy and its inhabitants. Their arrogance is surpassed only by their excesses, and their often quixotic wars of aggression that are merely thinly-veiled resource explorations.
2) They are IMPERIAL JAPAN: They burst onto the galactic stage after a long period of stagnation and now they want to build a huge empire. Trouble is there's one big fucking empire already sitting in their way (the Federation) and once upon a time they tried to knock over this empire to continue to expand, failed miserably, and got their asses kicked. In this sense, Romulus is what would have happened if WW-II had ended with an armistice immediately after the Battle of Okinawa, with the Japanese Empire intact, still militarized, but otherwise contained.
3) They are VULCAN GONE BAD. I envision Romulus as a society of Vulcans that have also devoted themselves to logic, but using a different set of axioms. Where Vulcans tend to use a utilitarian case-by-case logic that requires alot of study and specified intelligence, Romulans use an all-consuming logic that is rigidly enforced by rote memorization and conformity. They are, in essence, perfect fascists. Think of the inhabitants of Libria in the movie "Equilibrium" and you've got the idea, though it's not the suppression of emotion per se, just the open expression thereof.
Simple side note: in my view, the "animal passions" suppressed by Vulcans in Surak's time is largely a function of hormones. Since Vulcan emotional responses are otherwise not overtly different from humans (when expressed) the only anomaly seems to be their mating habits. Vulcans, it appears, have intimacy issues; the desire to mate is the only thing that consistently escapes their emotional control, and in at least one case we have seen this desire manifest in the form of extremely aggressive telepathic attacks if not outright violence. It's possible that the main reason Vulcans suppress their emotions is because it makes sense to suppress ALL emotions, not just the problematic sexual drives that caused so much trouble in their past history.
In this context, the difference between Romulans and Vulcans is that Romulans chose to suppress their more animalistic nature with the strict centralized control of the state, rather than the strict INDIVIDUAL control of devotion to logic. Where Vulcans will keep themselves in check because they are trained to do so, Romulans will keep themselves in check because they know they'll be drawn and quartered by the Tal Shiar if they don't. In the case of the Romulans, this control evidently doesn't extend to captives or enemies, as we have observed in the past that Romulan officers will occasionally impregnate female captives from their various conquests and then raise the resulting offspring. It's difficult to imagine that these pairings are always (or even usually) consensual; Romulans are just not that charming.
1) They are IMPERIAL AMERICA: They consider themselves a Democracy, the most-free and most-enlightened people in the universe, they believe themselves to be exceptional and the envy of the galaxy. They think everyone hates them out of jealousy, and consider themselves the rightful military and economic masters of this galaxy and its inhabitants. Their arrogance is surpassed only by their excesses, and their often quixotic wars of aggression that are merely thinly-veiled resource explorations.
2) They are IMPERIAL JAPAN: They burst onto the galactic stage after a long period of stagnation and now they want to build a huge empire. Trouble is there's one big fucking empire already sitting in their way (the Federation) and once upon a time they tried to knock over this empire to continue to expand, failed miserably, and got their asses kicked. In this sense, Romulus is what would have happened if WW-II had ended with an armistice immediately after the Battle of Okinawa, with the Japanese Empire intact, still militarized, but otherwise contained.
3) They are VULCAN GONE BAD. I envision Romulus as a society of Vulcans that have also devoted themselves to logic, but using a different set of axioms. Where Vulcans tend to use a utilitarian case-by-case logic that requires alot of study and specified intelligence, Romulans use an all-consuming logic that is rigidly enforced by rote memorization and conformity. They are, in essence, perfect fascists. Think of the inhabitants of Libria in the movie "Equilibrium" and you've got the idea, though it's not the suppression of emotion per se, just the open expression thereof.
Simple side note: in my view, the "animal passions" suppressed by Vulcans in Surak's time is largely a function of hormones. Since Vulcan emotional responses are otherwise not overtly different from humans (when expressed) the only anomaly seems to be their mating habits. Vulcans, it appears, have intimacy issues; the desire to mate is the only thing that consistently escapes their emotional control, and in at least one case we have seen this desire manifest in the form of extremely aggressive telepathic attacks if not outright violence. It's possible that the main reason Vulcans suppress their emotions is because it makes sense to suppress ALL emotions, not just the problematic sexual drives that caused so much trouble in their past history.
In this context, the difference between Romulans and Vulcans is that Romulans chose to suppress their more animalistic nature with the strict centralized control of the state, rather than the strict INDIVIDUAL control of devotion to logic. Where Vulcans will keep themselves in check because they are trained to do so, Romulans will keep themselves in check because they know they'll be drawn and quartered by the Tal Shiar if they don't. In the case of the Romulans, this control evidently doesn't extend to captives or enemies, as we have observed in the past that Romulan officers will occasionally impregnate female captives from their various conquests and then raise the resulting offspring. It's difficult to imagine that these pairings are always (or even usually) consensual; Romulans are just not that charming.