The biggest issue with Shadowheart is that it is very easy to mess up the pacing of her personal story. The first time I played the game, I assumed that the tadpole was a real threat and that I needed to try and make some hard decisions about when to rest. This had the result of making Shadowheart come off as a aggressively fearful person which, understandably for the player character, makes it hard for you to act warmly towards her. In your mind, as the player, you've survived 4 days worth of battles but Shadhowheart will only see it as "day one" mechanically. Of course no one would trust you on day one. In this sense, I think the gameplay can unchain her personal story in a bad way.
The second time around, I took a long rest after every two or so battles and it completely changed her character. She went from someone who would effectively say: "Go fuck yourself" every time I would ask a question about our current predicament (Note: I play in Spanish and the translations change somewhat frequently so have that in mind) to someone who is genuinely afraid of the tadpole but, also, genuinely afraid about what's going to happen to her when she has to continue her mission. On my second playthrough, she seemed more tortured than defensive. Rightfully scared. To truly get this understanding of her character, I had to ignore what the game told me about resting which I think is a problem (A good quote I read on reddit about this situation: "You can lie to the character but don't like to the player" which I think fits in this specific scenario (although, I admit that I believe unreliable narration has its points at times.)
Overall, I went from disliking Shadowheart (& Astarion) the most to actually liking them the most. For the most part, I have fear that all of these characters will fall along the generic Anti-Hero turned hero, fantasy vibe that seems to be spouting up everywhere but Shadowheart & Astarion do seem to show actual weight and understanding of their actions when their facades break. I think it'll be interesting to examine these characters further when we have more information.
+1 I did the same thing Except for what you said about Astarion. I can't get over his sneering tone every time I greet him.
