I don't think we've ever had a companion like this though. In both games, he's put in situations where he needs help. This is the main thing I know about him. First, he needs Gregoir's advice on abominations, then he's imprisoned in the Circle quest. Then in DA2, he wants our help on various Templar quests. And asks our random advice.. like if he should detain Keran.. even if we might be blood mages ourselves. lol.
There's nothing wrong with it. It's just that he comes off like any other questgiver NPC: Dependent. In need of a hero.
It's a little different than other companions, who seemed to already adventure a lot on their own. Or cause a lot of trouble on their own. I can see all of them have a novel all devoted to them. They're iconic. Not sure so about Cullen.
edit: Wait, Sebastian also comes off as a bit helpless to me. He's a bit like my Cousland, but if my Cousland didn't have it in him to take out Howe.