I hope Sela isn't dead either. Somewhere within this ice cold being must be her Humanity but the books generally depicted her as incapable of a full heel-face-turn. Although Indistinguishable from Magic was the first book in a while to make her sympathetic, Imho.
That was actually one of the things that made the character of Sela so interesting to me. She walked into the Enterprise conference lounge, lays out her life story, and then tells Picard "never doubt" that she is fully Romulan, when, on his part, all he has is her word that she even is Tasha's daughter and that her outlandish story is true, that she is not a piece in some greater Romulan plot. He had no reason to doubt in the first place, but she had to say that. It was a story thread that seemed to be begging to be picked up on, but TNG never did and quietly swept Sela aside.
That said, though, I can't really picture her character arc ending differently. She was stuck in that moment that she called for the guards, got her mother found out and executed, and made her choice to be nothing but Romulan. That moment defined her life, and she couldn't move past it. More, she refused to. If she had, it would have been her admitting that she was wrong about the Federation, that she had made the wrong choice to embrace her Romulan heritage and shun all things about her that was human. That was the whole point of her 'patriotism.' Her actions were made on the basis of 'if we do not balance the field, the Federation, the humans, will use their advantage and wipe us out.' If she admitted that she was wrong, that the Federation wouldn't take that step and make a preemptive strike on the Empire, then she would be admitting that there was something about the Federation that was better than the Romulans, that they were genuine in their beliefs and attitudes of peaceful coexistence, and that meant that she had made the wrong choice in getting her mother killed and staying with her father and the Romulans. That was why being sent to the Federation was her fate worse than death - it would have been coming face to fact with the fact that she was wrong.
Given the set up, I can't picture her story ending differently. I found her intriguing enough that I would like to see an alternate storyline where she comes to accept her humanity, but I can't see how the story of Sela as told here could have ended differently.