Romulans often get the short end of the stick. Originally meant to be the primary villains of TOS, a role which ended up going to the Klingons. Out of 11 movies, only two featured Romulans in any relvant way, and in one they took a back seat to a newy introduced alien of the week and in the other their homeworld got destroyed. After 45 years they're still considered bad guys, with previous attepmts to make peace forgotten/ignored.
So yeah, it doesn't surprise me that we've never had a prominent Romulan character. A damn shame, too. Trek has given us some interesting one-off Romulans over the years, I'd love to see what they do with a recurring one.