Excellent acting, excellent production, even liked the way they took the story into a depression era mood instead of the upper class Art Deco decadence... really nice idea.
But wow did they have to take it so far into the bleak hellish coldness? Poirot comes to Broadchurch? The whole point of crime stories is that they play off the ambivalence of fascinating social mores and customs, scientific curiosity, interesting relationships.
They are a paean to curiosity and the search for order, not obsessively staring into the gaping black wounds of the soul.
A relentless exercise in stripping away all denial and defeating the joy of it. Broadchurch worked in Broadchurch, not in Agatha Christie.