But do we really miss the content, if we bring certain Origins as party members. Let's say you have Shadowheart in your party since day 1, will actually playing as Shadowheart be that much different? You'll experience her story and quests, she will participate in dialogues as well, albeit from another POV.
I'm not really sure how it works, maybe you will correct me.
I think you'll miss out on her back story? And other parts.
Like with Astarion you might miss out on how he became a vampire? I don't know.