Here's where the disconnect breaks down for me: a good enemy has to have a good reason for things they do.
Looking back on the history of the Romulans, they seem to be the bad guys simply because they are the bad guys. Star Trek firmly setup they are treacherous, but not exactly why.
I'd argue the Durass Sisters weren't pawns, but rather power hungry. They wanted power and would use the Federation OR the Romulan Empire equally to maintain said power.
In the case of the Federation, this actually gave raise to allow for a Klingon led diplomatic camp (albeit, a half hearted one) with the Federation to Romulanus.
The key to making sense of all this, for me, is what motivate(d)(s) the Romulans?
- Did they want power?
- Do they hate the Federation so?
- Do they want to control so they can isolate (like the Founders) ?
- Do they simply want to rule?
- Do they want to bolster they're military position?
For me, unless you can bring about a logical reason why the Romulans want to drive a wedge between any thing that leads to potential peace talks in the long run, this whole incident actually provided one heck of an oppourtunity for the Federation to pursue peace through the initial duplicitous acts of the Durass Sisters.