She was a decent (far from top, but not terrible) hero on release. As with many heroes, time and power creep have been unkind to her. I would choose Thoth-Amun over Khiona at this point.
Khiona at average -
Thoth at fast -
Khiona would need additional 100% damage (or something like 400 & minor nearby) plus att buff to all in order to be usable