I think Atris really just needed some loving. One night with the exile would've set her straight.
As for the concept art, I think she was originally supposed to be the exile. Female canon after all. Or maybe that's just wishful thinking.
On topic, I liked Atris as a character. She needed a serious attitude adjustment, but I did pity her. She seemed like yet another victim of the poor decisions of the council. Going to war is not going against the LS. If the council had acted on behalf of the people of the galaxy, and had been self-sacrificial instead of self-preservatory, things most likely would have been very different. Atris may never have fallen, being free to follow the Revan, Malak, and the exile freely, without the emotional conflict of "betraying" the council, the Jedi, and her own moral code. Revan and Malak may never have "fallen", with all the masters there to counsel and strengthen the younger, more emotionally susceptible Jedi. In other words, Atris was simply already cut to ribbons internally by the strain of being pulled in two very different directions by two different attachment with what were, to her, very real, very justified reasons. Some may look at that as simple weakness, and maybe it is. But Atris is human, and humans are social beings, we all sometimes need companionship. Atris didn't feel as though she had that. She couldn't go to the council with her feelings, because she couldn't accept her own feelings. She couldn't follow the exile, because she couldn't bring herself to defy the council. In the end, feeling friendless and alone, she embraced the dark side, and it answered her call for companionship. The dark side became her "friend", her confident, her solace. The holocrons she gathered became her council, and she, still unwilling to admit she had abandoned all she knew to be right, masked her alignment with rationalizations of good intent. In the end, she fell, and Kreia's words embodied Atris' position best: "It is such a quiet thing, to fall. But far more terrible is to admit it."
I voted for "She was cool."