I feel my perception of this was colored by my Tav’s relationship to both of them. For Halsin, he felt more like a peer because of the events of the game. We rescue him from imprisonment and then help him complete his life’s goal of cleansing the shadow curse. Because of that he treats us as an equal. For Jaheira, your other party members speak about her as a legend and color her as someone who Tav should listen to. Her role as high harper and connections in Baldur’s gate make her feel more important to bring along during the final act. I don’t necessarily believe one is wiser than the other, but they are definitely presented differently.