There was a time when detectives occupied a different existential plane, emotionally distant from the crime. Poirot or Holmes arrive at the scene not with baggage but with pure logic and deductive thought. Detectives had many eccentricities, which made them unique and interesting, but their nonconformities never compromised the investigation.
But today, the detective characters have become more invested in other characters and the plot, both emotionally and socially. At the same time, they are shown to be as socially inept as their predecessors or more. Before, the crime and its detection used to be complex, but in today's novels, the most complex element is the psyche of the detective, and then only the plot and other aspects are considered. It seems writers have this notion that the detective has to be flawed and emotionally drained, so that the investigation poses obstacles due to this aspect and not because of the complexities of the crime itself.
When we analyse the chronology, it can be noticed that classic detectives like Dupin, Holmes, Poirot, or Miss Marple operate totally above the zone of the plot and the other characters. Then came the era of the hard-boiled ones like Sam Spade or Philip Marlowe, who had an emotional connection with the plot, mostly by way of a sultry beauty. But in the end, with the beauty conveniently out of the way, they lunged back into their exalted position.
Then it was time for another crop of detectives to emerge—the ones who bear the cross. Alex Cross (pun unintended), John Rebus, and Bosch are the ones that can be named off the top of my head. They are the conscientious ones. They are bound by duty to be impartial, but for them, finding the criminal and bringing them to justice is also a personal act of redemption. Their biases affect the delivery of justice, as they are prone to errors by virtue of their conscientious nature. But they attain the final vindication, and all their toils are rewarded by their conscience. In these stories, the crime element is relegated to the background, and more mileage is given to the character arc of the detective.
After seeing the enormous success of the final kind, many writers started developing detective characters with deep flaws, thinking that readers would empathise with their protagonists by relating to them. The emotional level of the detective in these stories is well below that of the plot and other characters. I will term them "pathetic detectives". I felt this recently while writing about a detective novel. But then, I wasn't able to put my feelings into words properly for fear of digressions that might lengthen my article.
The first pathetic detective that I encountered was Cormoran Strike in The Cuckoo's Calling by Robert Galbraith (a pseudonym of J. K. Rowling). I read three installments of the series, and by the third, I concluded it was futile to go on. The flaws and disabilities of Cormoran Strike were not at all relevant to the central crimes that were committed. With each installment, Strike became more and more pathetic and incompetent due to his disabilities and emotional baggage. By the third one, which was more of a romance than an investigation, he was cutting a sorry figure.
There are a few more novels that I read after that in which the detective is made to have many flaws and personality quirks only to elicit an emotional response from the reader—either sympathy or laughter. In many well-written novels, I feel that the lead character is written very well, but the central plot of the investigation is thin and banal. For me, the primary purpose of reading detective fiction is to enjoy the depiction of a well-executed and complex crime, the fruitful investigation by a competent detective who is able to detect things that others miss, and the final surprise reveal that makes me wonder how I missed that.