The only way this movie makes sense is if you have no familiarity with the book or previous adaptations - otherwise it gets very confusing. Example? Two characters have essentially been amalgamated into one, who then turns out to be the lesbian lover of her supposed maid! I mean, hell, let's be as PC as possible while we're going about it, right?
Not only that, but the film falls all over itself to be as diverse and inclusive in the casting as possible - why stop there, and not just make Poirot a little person who's biracial, trans, suffers from AIDS, and is blind and mute? I personally hate the way classic books and movies are being butchered for political purposes - it's insulting to the authors, and patronizing towards the audience. If they want to be diverse, great, go and write some original material that logically encompasses it. Next, they'll be producing another film about the battle for Iwo Jima, making sure that half the combatants - on each side - are women.
Furthermore, having two black women take key roles in the story beggars belief, simply because of the period the movie is set in. Aside from bastardizing the author's original characterizations, a young black woman falling in love with a well-to-do white male from America would have been considered scandalous in that era - transplanting modern sensibilities to the past, however admirable the intentions, simply looks ridiculous. The fact that color is never raised in the mother's objections to the relationship makes it look even sillier - it would have been front and center in that era. The film could even be considered disrespectful, even insulting, to the many people of color who had to endure all manner of intolerance and racism in those days. Better to present a sanitized view of whites who all accept mother and daughter's presence among them without question.
Lastly, you would think they could at least have tried to get the basics right in terms of geography when it came to the CGI rendering of the pyramids in the 1930s. While there is evidence to believe that a branch of the Nile did indeed course by the pyramids in ancient days, there is no way that the river ran close by the Sphinx in the pre-WWII era. In reality, the Nile is about five miles away at its nearest point.