[Osse]

You could say that any of the characters in any book are, as literary devices, gateways for the reader to insert himself/herself.
I am of the opinion that Tolkien, with the knowlege that he had of the human mind, and english language, placed Tom into the story deliberately as an enigma. He was a character that would keep the interest in his Middle Earth smouldering, long after his readers had finished the books. Using a character that he had already created, he provided us all with something to mull upon. Whether Tom's inclusion (as an enigma) was accidental at first, or completely deliberate, who knows?

The essay in my opinion was great, but unfortunately failed to convince me. I agree that The House Of Tom Bombadil was placed in the book as a kind of relief from the heavy and dark matter, but I do not believe that Tom and Goldberry were Us (the readers).
T&G were part of middle-earth, though they may be implacable (as far as WHAT they are) they are none the less part of the book, not a place in the book for people to insert themselves, relate to yes, but not insert themselves.

*I found the essay finished a bit abruptly, did the author run out of justification, or deem that enough was given?*

Osse