> The basic conception of the argument (“Is [God] willing to prevent evil, but not able? then is he impotent. Is he able, but not willing? then is he malevolent. Is he both able and willing? whence then is evil?”) still seems valid if a God has created a karmic system.

The difference, as I understand it, is that the free-will argument requires the existence of a creator who is either impotent, malevolent or evil (or some combination of all three).

A karmic-based system requires no creator to exist.