Nice finds and suggestions. I'd be happy with any list so long as Remans were removed from it (yes I know this will not happen). They were a garbage addition to Nemesis that distracted what could have been a real opportunity to tell an interesting Romulan story. Anyone else looking to see the same?
Unfortunately I do not believe Romulans will ever be a meaningful player option in this game. If something resembling a faction does appear, it will be so far down the road and the game will be such a marginal concern, that I do not imagine the Romulan Faction making a difference.
It really is a shame. Generally the only reason I consent to play anything Trek (RPG, MUSH, etc.) is if I can play a Romulan.
The only real chance for STO is if Romulans are a more cosmetic faction. They should have 3 new classes (break from Tactical, Engineering and Science). They might open up 3 faction PvP (we've yet to see a single addition to 2 faction PvP though). Diplomacy could be replaced by some sort of meanignful spy/Tal'shiar progression. With those three changes, one could experience the already existing content of STO through a new lens, thus saving a lot of content development time.
I forgot to mention that the Romulans control a great region of space in the Beta Quadrant. Their military may not be entirely diverse, but their Empire certainly is.