Freedom of answering and rolling dices because you choose to speak with your main rather than someone else ?
I agree that Larian make a good job with how quests can be solved, sometimes depending your class or your race... It's very impressive and I'm still discovering new things.
But it does not prevent to have a specific role in the story. Like Shadowheart with it's artefact in exemple. He could in exemple be the only one to make dreams and have special powers... We'll discover why later.
Now your character does not matter at all. If you're not in the story, the story remains the same. Why even play this character ?
You're not writing anything else than what is planned except for details. That's cool, but it's still details that does not make your character look invested in his quest. He's just another guy with a tadpole in it's head that does not find a cure and that's going to travel to the moonrise tower with his 10 mates.
You're even not really the leader or something. You're just nothing. Just random Tav that has the exact same story as everyone else.