Well it's really simple - the devs decided that and there's no helping with that. There are many fictional characters who suffered an unfair fate, so I don't exactly get your point. Someone above mentioned thay Dammon's VA recorded the finish to her questline or something like that. If it was true, why would they cut it from the game?
And that's the question. Maybe some major bugs, maybe some plot holes in the story, maybe lack of time, because the release was close and even planned to be a month earlier. In my opinion it was combination of all these factors. Or maybe you right and they do not plan to fix her engine at all in the end. But all clues we have looks like it was possible to fix her. And at the end they don't have even time to remove these clues from the game.
