+1 it's disheartening sometimes... Like once, I saved certain guy's family from execution and only the main character talked to them. Then I found this guy and he helped me with a loooong battle. The fight ends and as I'm super concerned about my main character's position (cause obviously the guy would comment on the fight we just survived) he ends up talking to my healer, which seemed to be next in initiative before the fight ended -.- He asks for his family and obviously the healer knows nothing about that, and I'm like "can you ask me, please? I know your folks!"
Anyway... Auto-dialogue should target always the main character... Companions can interrupt when they desperately need to talk to that NPC...