Those are all classic films that maintain a documentary feel to them. They are rooted in the dark and gritty world of urban decay. A sense of realism is present in these films that set them apart from over-the-top action found in most crime films or action-adventure spectacles. If Daredevil follows the trajectory of these types of films, the overall finished product is going to be both very real and very dark.
Do not think for a minute though that Netflix will allow the material to be excessively violent and morbid. Going too far in the adult direction will end up turning audiences off and Netflix and DeKnight know this.
What saved the Daredevil comic book from cancellation in the early 1980’s was the decision to allow Frank Miller to take the hero down a path radically different from other titles. The TV series seems to be adhering to this approach, too.