Romulan AI is initially slow to build. In fact, it doesn't do much of anything. Builds stations out the yin yang, but ships are kinda ignored. Not too big a problem, but for Skirmish fights/AIvAI stuff, it can be a bit of an issue when a Dominion AI rushes to build a lot and wipes out a Romulan AI in the first 5 minutes.
Yeah Ive noticed that too. Rommies are indeed slow to start but then pick up pace when they can build big ships. So I thought that was because of race specific AI(Rommies in st universe do indeed mostly build big battleships, the exact opposite for the Dominion

)
There's another issue with the Romulans, specifically the cloaking devices. If you cloak some ships, it automatically goes to Yellow Alert. However, when you decloak, it sometimes doesn't go back to Red Alert. Nasty surprise when the enemy gets off the first volley and only one or two of your ships respond. I didn't notice the first couple of times because I was busy elsewhere and it took me awhile to figure out why it was I was losing so many ships and then when I did see it, why they weren't firing. I haven't figured out if anything triggers this, but I suspect it might be if you cloak, change alert status, then decloak.
Yeah that is annoying lol Especially when u dont know about it

But when u figure it out, it shouldnt be much of a problem anymore. Though it would be cool if they fixed it

The Dominion AI has what I think of as a "glitch" but I suppose this is more of an observation. Any Dominion AI builds the Prototype ships and doesn't use them for attack, as would be only proper. However, if those prototype ships are attacked, they're instantly thrown into combat. And usually wiped out fairly quickly. Not usually so bad, because if they ARE attacked, it's usually because some enemy fleet is knockin at the door. However, against the Romulans, the issue becomes a bit more...interesting. Using a Tal-Shiar station, it's possible to of course use the warp core attack on the prototypes. Cool, except for it causes the Dominion AI to go into a single minded frenzy where it orders every ship it has, including it's prototypes, to ignore everything else and go for your Tal Shiar station. That would be a BAD thing for you, except for the fact that when I say it ignores everything, I mean everything. That AI's ships generally don't attack anything but the Tal Shiar station, with the end result that they're easily anhilated with few or no losses on anyone elses part.
It seems the AI somehow "knows" where the Tal Shiar station is when u use core breach on them, and then it sends everything its got against it. The AI acts the same way about that station as if it was attacked by another ship, thats why they do that. And I doubt it can be fixed

The Tal Shiar War Core Detenation weapon seems a bit underpowered. Seems like blowing up the warp core ought to, if not destroy the ship outright, at least disable alot of it's systems. Also, the Spy function for the station could do with lasting a bit longer. Nice for revealing where stations are, but that's of limited use really.
It was more powerful in BETA 2 and it was SOOOOOO unbalanced that it wasnt even funny in multiplayer games. It is ok now, u can significatly cripple any ship with that thing. So I think that is ok

Though u are right when u say that a core breach should destroy a starship heh, so maybe a name change is in order

Spy special ability is good enough imo, I mean it does reveal EVERYTHING the AI has built thus far, no need for it to last longer