Excellent post, Child!
And I have to say that I totally agree with Juliet Waldron (and much of your post) in that Frodo is simply not in the films. He has been replaced by a character who does little more than play the part of a whining passenger, with none of the wisdom or chances to show his mettle that we see in the book.
Furthermore, I detest with a passion any change in any screen adaptation which is done 'for the modern audience'. Unfortunately, PJ has ... ahem... 'adapted' Frodo, Faramir and Aragorn so much as to be almost unrecognisable from their original characters.
Yet again, I keep coming back to 'WHY???'. The wonderful characters are all there in the book. The book is one of the most popular in the world, even with a 'modern audience', so why the heck would you change things so much?