You can argue that she offers a pretty good stance on rhetorical theory but to me she is just an author/activist. I don't want to seem mean nor am I putting the great Helen Keller down in any way I just cant make the connection between her and the definition of a rhetorical theorist. What she may offer is insight on particular issues within the rhetorical community, which I believe is what this article is making clear (defining the clear relation to her work and Burke's). But I would not call her a theorist nor do I think she would.
In the article there is a quote remarked to Keller from a "friend", "I have heard men say," How can a deaf blind from infancy know about life, about people, about affairs? It is impossible for her to have a first hand knowledge of what is going on in the world"". And Keller replied along the lines of an analogy that justified her position to understand the world. Something major happens in the world like 9/11, I wasn't there nor were you but you understand what happened that day. And by all means that is a great answer, possible the most "sophisticated" answer that one could make from her position. But from what I have learned through this major with a stressful emphasis on rhetoric is that we define our world and perceive it with the use of our senses. And this is where i find myself sounding mean but I just don't think she is in the position to rhetorical theorize about the world. Instead I think we should just look at her work and see what rhetorical theory she could offer.