^Understandable. For the most part, she was portrayed as a 1-D villian. Y'know, the Villian-You-Love-To-HATE!
Still...I think there is a "tip o' the iceberg" with her....
See, when she and Picard first come face-to-face, she tells him what happened to Tasha--how she died. She goes into a lot of detail, which, frankly, implies that the scene had been playing in her mind, over and over for so long, that she had to let it out.
As she tells the tale, her tone gets more and more intense, and when she says, "My father offered her a life, and a home... and she betrayed him!", she all but shouts it out.
I dunno...but it seems to me that when she says this, she's trying to justify to Picard her actions back then--her betrayel of her mother.
So...when she declares, "Everything that was human in me died that day. All that's left is Romulan--NEVER DOUBT THAT!", Picard, of course, shrugs and says, "Doubts? I'm full of them."
I'm no shrink, but... it looks as if she is consumed with guilt, and she is telling herself that it was her mother's fault. She hides her guilt, in effect, by becoming the mortal enemy of everything her mother stood for...which, by the way, is represented by Picard.
Hence, she tries to gloat with this tale...at first. But when she gets into it, she becomes very emotional.
In "Unification", this insecurity is hinted at. When she grumbles about how difficult her life has become, because of Picard, Data, and Spock, Data says, "Perhaps you should consider another line of work."
She looks pissed off at this, to say it mildly.
When Spock refuses to go along with the plan, she actually explodes. "I hate Vulcans! I hate the logic, I hate the stubborness," etc.
It would be most interesting to see if this insecurity could be explored further... it would go a long way towards promoting her from 1-D status, to put it mildly. Hmm....
(Jots furiosly in notebook....)