David Foster Wallace appeared to be trying to write himself out of nihilistic depression, and ultimately failing. Infinite Jest is largely about the corrosive effects of addiction on meaning-making; and his unfinished final work The Pale King takes place inside an IRS office, that is, the most boring and meaningless place conceivable.
What about the original usage, that is, writers as soul-engineers? I can see many of the most creative novelists in that light. They are exploring the architecture of the self, their characters often represent various stances the self can take to the world – this is kind of soul-engineering. Writers like David Foster Wallace or Vonnegut don't just tell a story, they construct an entire stance of their own, a stance which is somehow shared with their readers. To the extent this construction is deliberate, maybe it is a kind of engineering.