My acceptance, and even appreciation, for what Jackson did has grown over the years. I am prepared to accept that different artists working in different mediums will tell a story differently – even have to present it differently. But I still believe that Jackson's films are not, in spirit, true to the point of the story as Tolkien told it. In a simple metaphor, I might say that Tolkien presented a story perhaps with some gray, but told mainly in black and white. Jackson retells the story in shades of gray, which does happen to maintain some white and black at the ends of the spectrum. Tolkien created a tale of heroes, although one with a realism of characterization not found in lesser imitators; Jackson is fascinated by – and expands on – the imperfections implicit in the humanity even of the Elvish and Dwarvish characters.
Jackson's vision increases Aragorn's doubt, and this is the most excusable fault. After all, Tolkien at least wrote that into the original story. Less palatable is his presentation of Elrond as a pessimist, if not a defeatist, a far cry from Tolkien's vision of a kingly Elven prince. But where Jackson really loses a handle on the story is in his portrayal of Tolkien's most heroic characters. Frodo and Sam's unshakeable trust in each other – which even the Ring fails to subdue until the very end – is replaced by an object lesson in trusting your friends, for the sake of which the bond of friendship is disrupted by Gollum, of all people. The same thing happens to Faramir – in Tolkien's hands, a most perfect gentle knight if there ever was one – who falls to temptation, again in order to teach the lesson of trust, or honesty, or something.
In short, all that is left of Tolkien's struggle between good and evil is the struggle against evil. Gandalf, in The Hobbit, questions Bilbo's loose use of "Good morning!", but I do not think he would be much happier with Jackson's idea of 'Good', which seems to be defined merely by an opposition to 'Bad'. Lest I seem to be faulting Jackson too much, I should say that this tends to be a common fault of modern fantasy. The taste for 'realism' has lowered our expectations for artistic heroes, even when it doesn't degenerate altogether – as in much of George R.R. Martin's or Alan Moore's work – into dystopian nihilism. To paraphrase whoever you've decided to attribute the quotation to today, all it takes for evil to triumph is for 'good men' to be merely 'decent', to be nothing in particular.
Tolkien wrote that The Lord of the Rings was not to be seen as paralleling the events of the Second World War, and noted that if it were the Western alliance would have taken much more pragmatic measures. Tolkien was perhaps himself more influenced by earlier wars in his own life, primarily the First World War, where it seemed that some idealistic spirit still endured, even if the nature of the fighting and the new technology with which it was conducted was horrific in fact. But to us now – and I think to Jackson – the idea of the hero, of the good man, has been deeply influenced by the wars fought over the last century, with a nod perhaps to the "Great War", but really beginning with the 'Greatest Generation' that left ordinary jobs and lives to fight totalitarian expansion, and continuing through the sometimes pointless wars and interventions in Asia, in the Middle East, in Latin America...
If I seem to be wandering far afield from mere film criticism, forgive me. If I might be so bold as to pretend to look inside Peter Jackson's mind, he has seen all of these historical events unfold, and to him what rings most true in Tolkien's work is the narrative of the simple man doing what is necessary, because someone has to. Where I see the story as a heroic saga, with Aragorn, Faramir, and the rest as noble examples to emulate, Jackson hears most strongly the sentiments of desirable normality and to him the untouchable heights of Tolkien's Galadriel, Faramir or Imrahil are the artistic inconsistency. I do not think his narrative allows properly for the way in which even Sam – the most 'common man' of the Company – has as an ideal "the brave things in the old tales": praising the people who did the deeds (whom again even, or especially, Sam recognizes as being not that unusual) not exactly for being innately heros, but more for performing heroism: recognizing them not for innate goodness but for the deeds themselves, the Good done. We culturally are used to idealizing the Normal Person in all his humanity and calling that, good and bad together, "good" (or at least good enough), and I think Jackson's understanding of the story is diminished for lacking a view towards anything much higher.