After playing EA I changed my mind on Shadowheart. My reaction to her was very negative when the companions were announced. Some things haven't changed, but as it is now, she is definitely the most fleshed out companion. She gets a lot more of dialogue options, and more often appears in random cutscenes. She is the most chatty of the bunch, ironically.
What I do think is that her appeareance is very badly designed. Don't get me wrong, she looks amazing, but are our characters truly that oblivious? It is very clear in the way that she is dressed that she is a sharran. Yet it is supposed to be some sort of big secret...?
Shadowheart: Alright. My secret is I worship Shar. There, I said it, please don't overreact.
Player: OH MAI GAD GIRL RLY? I'M A CLERIC AND I TOTALLY DIDN'T NOTICE. U SO SNEAKY TEE HEE.
P.S: I ended up romancing Shadowheart in my playthrough, completely unplanned. And I've ranted and hated on her nonstop on this forums. How awkward that was.