Given that, as you say, Romulan technology is cutting-edge in most respects, and that the Star Empire was a long-standing superpower...I think the Romulans would
hypothetically have been poised to become the dominant power post-Borg Invasion. Would have, if they hadn't already suffered several catastrophes, not least of which of course is their division into two nations.
Really, prior to the Borg Invasion they were in a pretty bad way. Certainly not ready to assume supremacy if their neighbours fell into difficulties - they had too many of their own. In fact, in Articles of the Federation
it's stated that they don't really count as a superpower anymore, which is why Bacco inviting Tal'aura along to the summit with Martok was "a courtesy". And why in Taking Wing
Starfleet Command is quite happy to violate the Treaty of Algeron on the basis of "tough, we're stronger than them now". With the Remans gone, the Romulans' ability to swiftly and cheaply get the necessary resources for maintaining, yet alone expanding, the empire must be very difficult. And that was before resources were halved by the split.
Even before the post-Nemesis
struggles, it seems to me like the Romulan nation had been in decline for some time. Novels like Catalyst of Sorrows
suggested that the Star Empire's economy wasn't as stable as it appeared, because the leaders kept channelling as much as possible into the military and weapons research leaving many regions in poverty. The Romulan bark might have been much larger than its bite; sure, they can build intimidating warbirds bigger than anything else in local space, but that massive gleaming starfleet is covering for several under-nourished farm worlds and crumbling city districts...I always assumed the Romulans were making a valiant effort to appear economically prosperous but really they were quietly floundering. I don't think they could have truly expanded the empire very far, because I doubt they could truly maintain their current military might for long. They're not like the Dominion, which can bounce itself back in a couple of weeks. Catalyst of Sorrows
and others also said the treasuries were still depleted as of the 2360s thanks to Dralath's mismanagement a couple of decades earlier. I think Dralath pretty much put a stop to any hope the Romulans had of returning to the expansionist "glory days" of the pre-Federation 22nd century. Of course, with the Dominion War, the Romulans were weakened militarilly and economically again...to the extent that when the Watraii attacked they couldn't do much more than tighten security around the core worlds and demand assistance from their Federation allies (With Zife wringing his hands the whole time until Spock sorted it out for them
, it's all fallen apart. In the old Star Empire, Tal'aura can't even feed many of the colonies without help from outside. And the Bloodfire plague is still out there, I believe, along with who knows what other diseases. That's probably affecting both nations (we don't know exactly where the Kevratan worlds are).
The Star Empire lost the farming worlds, and the IRS must have lost some major assets too. And how many shipyards or productive subject worlds in either state were destroyed by the Borg? I've tried to loosely estimate how much territory the RSE has left (or how much useful territory, anyway). We know Aventine
made its ambush of a Borg Probe near Devoras. On the Star Charts (and obviously taking into account the problem of 2D/3D which makes it very unclear actually how deep into Romulan space Devoras is), that's potentially significantly deep. We've been told a line from Nimbus to Dewa more or less shows the RSE/IRS divide, so I drew that. I like to think the area within that vaguely oval squiggle at the bottom (I'm an artist!
The Imperial Romulan State seems eager, post-Borg, to build on its good relations with the Federation. It even seems okay with the Klingons (In Destiny
, Jovis seemed to get on quite well with K'mtok, if only to show a united front against Kalavak). Apparently, according to A Singular Destiny
, its economy is stronger and it can at least feed itself. Its best bet would be to continue strengthening ties with the Federation and Klingons, I assume. The RSE, meanwhile, is totally dependent on outside support. Tal'aura's managed to pull a rabbit out of her hat and reclaim significance for her nation by making it a leading member of the Typhon Pact. So they're a superpower again...but not really. They're just part of one. And already it seems they're quietly competing withthe Breen and others for dominance within it. And I wonder how Breen or Tholia will feel when Romulus is destroyed in 2387 and the Romulans presumably become a burden, not an asset.
We'll see a lot more, I guess, when Rough Beasts of Empire
PS: Something I've mentioned before is that the whole Typhon Pact business potentially gives new significance to the RSE/IRS divide. Or it seems so to me. From what we've seen so far (and acknowledging we haven't got Rough Beasts of Empire
yet), Donatra is pretty much just waiting for Tal'aura to screw up and then she'll let the two nations slide back into one, only minus Tal'aura. And A Singular Destiny
showed us that the common people don't really care which side they're on; it's just the noble classes squabbling. So, until now, there was no reason why they wouldn't join back together at some point. But if the citizens of the two nations start buying into their new alliances, ideologically, it might actually give them genuine reasons to dislike each other at every level, not just the top level. The Federation/Klingon Vs Typhon Pact "cold war" might actually prevent any Romulan reunity. At least, that's a pondering I had.