How can I limit the Fluency Enhancer to only suggest changes that are truly essential for fluency?

Draftsmith attempts to suggest phrasing that will sound natural. Of course, "sounding natural" is always subjective.

In some cases, it will suggest changes that unnecessarily diminish the author's voice. In those situations, you can always decide not to accept a suggestion. Also it is easy to edit the suggestions so that only the most crucial changes are applied, while the author's voice is maintained. Edits can me made directly in the "Suggestion" box within Draftsmith.