Well, both are safe as long as the writers remember that, to qualify for the Star Sapphires, one must have "great loss in [one's] heart". The ring takes people who feel sorrow, as opposed to the red ring, which takes those who are consumed with rage. Well, unless they painfully construct rationale along the lines of "Diana's not an Amazon! She has a hole in her heart to be filled!"
I was thinking she could be recruited into the Indigo Tribe to help them communicate with the universe. That'd use her established aptitude with language and diplomacy.