To be fair to the Branagh film, many of the changes were mandated by the Christie estate, who were one of the companies that produced the film. With the end of the Suchet adaptations and a noticeable decline in her stories being optioned, in 2015 after the estate regained the screen rights her grandson, Matthew Prichard, announced that with only 32 years left on the clock before copyright ran out they wanted to sex up and make adaptations more in line with contemporary movie and TV trends - their specific template for Tommy and Tuppence, for example, was The Avengers (as in Steed and Peel) meet Indiana Jones. They wanted an interconnected movie and TV universe that was action packed, modern and multicultural (the original Poirot film series died because they almost exclusively appealed to an ageing white middle class audience that rarely saw films on the big screen) while keeping the 'unique Christie DNA.'. As with the Bond films, the new elements created specifically for new screen adaptations could be copyrighted even after the novels fell into public domain (which is one reason why recent BBC TV adaptations have different endings to their source novels).
In this case it's the author's estate rather than the filmmakers driving the changes.
Maybe that helps explain why they're all a bit shit.
Quote:
Originally Posted by Aclea
Is it really any more depressing than seeing Miss Marple turned into a loveable eccentric in a series of 60s comedies bearing little relation to their source or nominal character?