"The ethical question that is here to be discussed is this: In adapting someone else's work, do you owe any fealty at all to the original author's intentions? Would it be a problem, for example, to do a Christian Mein Kempf, you know, and actually make it a lovely, inspirational piece about the power of the human spirit? Do I, as a writer, have a right to take something that has come out of someone else's brain and heart, and using it's name for notoriety and marketing, gut out its heart?
Obviously, it is one thing to violate source material because you are too stupid to understand the heart that you are gutting. This diminishes moral culpability, although it seems to me you could still end up in hell for having the hubris not to step aside when a task is so far above your skills and experience. (I would call this obama-ishness.) It is quite another problem morally, to hate the heart you are about to gut, and then willfully subvert it.
In the case of this new version of Brideshead both of the above are coming into play to render the project a mess. The task was above the intelligence, insight and skills of the adapters, AND they hate what the book is really about: "that Catholic thing."
It appears that screenwriter Davies, a typical naughty minister's son, had to do away with the elegant dialogue of the novel as well, since it so elegantly expressed the Flyte family's dedication to and struggles with their Catholic faith, in order to produce what one critic called, the most romantic gay love story since "Brokeback Mountain". In the BBC series, the relationship between Charles and Sebastian is explained as a phase of adolescence which is outgrown, not a lifestyle choice, and to make it a gay love affair is the worst kind of revisionism.
Avoid revisiting this strange new Brideshead, and rent the BBC series from your library or better yet, read the novel.
John Muldering offers a similar if less clarion warning not to expect a faithful film.