Braga is full of crap, you could easily show the Romulans, AS LONG AS THE STARFLEETERS DON'T SEE OR TALK TO THEM.
In 'Balance of Terror,' Kirk and company only see them because of a transmission, and they don't interact verbally at all till the end. This could be easily handled by any GOOD scriptwriter, so it's no surprise B&B can't handle it.
To them, a good script involves caves, flashlights, destroying a piece of ToS lore, and finding a way for T'Pol to get naked.