The themes and motives for criminal darkness in human beings, as explored in Arthur C. Doyle's Sherlock Holmes tales, are timeless enough that they can survive a transition to a present-day setting, changes in societal mores and technology, notwithstanding. Serial killings, forensics (in its infancy at the time of Doyle's stories), the old characters' quirks, such as substance abuse and attempts to recover from same, or military backgrounds; John Watson's Victorian-era service in Afghanistan becomes post-9/11 service in the same locale, etc. The more things change, the more they stay the same, I guess. As do the villains' motives, unfortunately, despite adjusting said motives to conditions in the present, but to say more would give away spoilers.
Holmes' being wrapped up in his own intellect might be a bit off-putting, making him a bit tactless at times when most of us would assume that some sensitivity to human suffering--caused by criminal conduct--is needed, and often succeeds only in making less intellectual types feel small and useless, but occasionally cracks show up in his cold, logical armor, showing that he's only human, and needs human friendship, or at least someone to whom he can show off his talents, hence his unusual friendship with Watson.