Storytelling tastes and quality vary significantly with time; what was an acceptable trope or style or what-have-you can fall out of fashion and not be acceptable to modern audiences. For example, modern audiences (for whatever reason) have become accustomed to expect a character to have arc; that is, the character will go on an emotional journey and end up somewhere other (not just in status or location) from where they started. Thus, in a highly prominent example, the very noble and kingly Aragorn, biding his time in the wilderness, becomes a man afraid of his destiny and bloodline (when he's afraid of nothing else) who grows to accept his kingship. Modern audiences would have been put off by a depiction of Aragorn that hewed more closely to the books. Likewise, Faramir.
This is not an "improvement" on Tolkien, or an assertion that anyone knows storytelling better than he did (though, I won't say there isn't anyone who knows it better), but an adaptation for a different audience, in a different milieu, in what is a different genre along multiple axes.
We can agree to disagree on this. As films, jackson's work is probably quite acceptable to most people. His treatment of LotR (and the "anticipated" treatment of The Hobbit) is not acceptable to me. That doesn't mean that I think every copy of them should be taken out and burned (though i wouldn't shed a tear if that happened), but I wouldn't recommend them to anyone who has the slightest care for either LotR or the integrity of written works when adapted for film.
Perhaps it's because I've known too many authors, and--indeed--have been married to one for 42 years and counting.