Klingons appear to be long-reaching adventurists, but Romulans could fit the picture of Soviet-style homebodies; quite possibly they would rework the ships to meet very different mission demands.
Good analogy, makes sense to me within the TOS portrayals. But wouldn't you expect the Romulans to be more "Spartan"?
From "Day of the Dove":
SULU: Trouble aboard the Klingon ship. Evidence of explosions, massive destruction.
KANG: You attacked my ship! Four hundred of my crew dead. Kirk, my ship is disabled. I claim yours.
SCOTT: Captain, we've not been able to get through to Starfleet Command. All subspace frequencies have been blocked, and there's too much radiation coming from that Klingon ship. It's a hazard to the vicinity.
Apparently, the massive destruction must have occurred internally and most likely in the engineering hull where 400 "of the crew" were killed.
The 40 survivors probably all came from the bow "bulb".
Now, Kang didn't say explicitly 400 Klingons were killed (that would merit the execution of 4,000 Federation citizens from a Klingon perspective if I'm not mistaken), thus we might be looking at 400 aliens (i.e. not Klingons) that did serve as "slaves" to run the ship in the engineering hull.
An analogy to a Klingon Battlecruiser might be the Roman Trireme
(Roman galley) where most of the operators required for "propulsion" were slaves. Admittedly, that's a crew complement you'd rather expect to see with the Rom(ul)ans, but maybe an explanation how they got their name during the Earth-Romulan War...from a strictly TOS point of view, of course.