Star Trek: The Next Generation featured one of the more interesting character switches for an actress. The show brought in Denise Crosby to play Tasha Yar, the Enterprise's head of security. Yet, right before the first season was to end, Crosby's character was killed off and Yar wouldn't be seen again until season three. In that one-off episode, Yar once again was killed off, this time by going back in time with the Enterprise-C, and was abducted by the Romulans.
She would end up giving birth to a half-Romulan daughter, Sela, who in storyline, allowed her mother to be killed due to her mother's traitorous ways. When Yar attempted to escape with her daughter, Sela notified the Romulans by crying out, not wanting to leave her father or the Romulan Empire.
It gave the character a sense of ruthless loyalty, so devote to the Romulan Empire that even her own mother was easily given up with no consequence. But people love to ruin a good thing. Giving Sela this duty that transcended her family made her so much more dangerous. She was devoted to her loyalty to the empire and she wouldn't be swayed from it.
In the recently published Star Trek: Defiant Annual #1 by Christopher Cantwell, Sela meets the original version of her mother, the one that died in the first season of The Next Generation and after meeting her, she comes to realize (according to ComicBook.com) that as a child, she cried out because she was afraid, and she only latched onto her father because he was all she had left. Cantwell goes as far as to say that the two didn't even have a relationship prior to Yar's death.
And in doing so, all that makes Sela interesting as a villain has been erased, all because one writer wanted to sympathize with a villain. This is what has plagued modern storytelling for so long; this need to deconstruct the villain to better understand them. It's a weak and often times destructive process that only serves to sour the aura and mystique of the character.
Doing this makes Sela no different than anyone else the crew of the Enterprise had to face and maybe that was the point of it; to take away her pathos. If that was the point, good job. If it wasn't, well, let this be a reminder that these characters only have the weight they do because someone brilliantly came up with their backstory.
You can't make already great characters better by adding to their origin, only worse. So stop trying.