Without knowing how you've done your play-throughs it's hard to say much of anything. I haven't done an evil play-through so I've only ever killed Minthara. I have been able to soften Shadowheart quite a bit but it did take work. I have seen enough from her that I can say she definitely does have depths to her character that have not been revealed yet, including hints as to her childhood. Meanwhile, as has been said, we've only seen at most a quarter of the game and that quarter is only a first draft. Not to say you're wrong or deny your experience, but it's not enough to make a final judgment about any character. We'll just have to see how things work out.
