To put it simply, she was wanting the death of the force. Kreia already mentioned how the force works through those who aren't force sensitive, which meant simply that she wished for the death of life. Too bad Exile could live without the force.
I managed it with the old "stay on the light path, but gain influence with Kreia" trick, despite the fact that it doesn't give you maximum influence with her. She seems a bit odd when she speeks about Revan. Probably because he/she, like the Exile was one of her more powerful students.
I grudgingly said evil. I'm under the impression that Kreia is a manipulative b*tch who was able to hide her evil well (even from Visas' force sight) and help the exile reconnect with the force to serve under her command.