At the heart of nearly recent procedural is the idea of a flawed or damaged hero. Normally, the primary (and very rarely the secondary) protagonist, will have some phobia, emotional pain or other mental or even physical impairment that will limit the efficiency of their job. From the transition of idealized characters to more realistic ones, we see that more and more characters in modern television have gone from “I’m the hero” to “If I solve this, I might feel better.”
Kolchak: The Night Stalker* is often cited as the influence of most modern science fiction procedurals. In the show, Carl Kolchak would investigate mysterious (and often supernatural) events for the newspaper he worked for. The show thrived on the fact that there were always weird things for Kolchak to go investigate on a weekly basis (hence it being a procedural itself).
The problem with Kolchak was not that he was searching for the killer of his dead wife (the basic plot for the 2005 remake Night Stalker) but that other people kept him from doing his job. The police or his editor would place constrictions on Kolchak and how he could solve the mystery of the episode. The mission of Kolchak was, essentially, that he find the truth.
Contrast that with The X-Files, another procedural that was based on the investigation of strange events. The two main protagonists of the show (because I refuse to count Agents John Doggett and Monica Reyes as anything other than annoying) would be sent or choose to go from their FBI offices out into the world to try to find the truth of a situation. (Why is the truth always “out there” and not just, you know, in this desk here?)
The main difference between the shows, other than it starred two people instead of the one, was that both Agent Fox Mulder and Agent Dana Scully were, in some way, “driven” to find the truth. Instead of just finding the truth, they were looking for their own reasons. Fox Mulder, for example, was constantly looking for his sister who had been abducted (most likely by aliens…or given away by her father…or was really actually an alien herself. I forget the true reason) when he was younger. That was his mission. (The show never really narrowed down Scully’s reason for searching. Sometimes it was her father’s death. Other times, it was looking for Mulder himself.)
Science fiction shows are not the only ones who have moved from “the truth ’cause it’s the truth” to “I want answers. I’m hurting!”. Medical procedurals have moved in the same direction. Earlier shows such as Quincy, M.E.* had the protagonist’s main problems being again the people around and working with him. Recent examples of a trend toward more flawed characters within the genre include the show House where a major aspect of the main protagonist is that is both crippled in one leg (he walks with a cane) and has an addiction to pain pills (for that same leg).
While not wanting this post to be extremely long, I will touch on some police procedurals as well. 70’s shows such as Columbo and McMillan & Wife* were idealized models of what people should be. These were people that solved problems and only had other people holding them back from getting everything done. The blooming of the “cop show” genre has exploded within the recent decade with a slew of CSI, NCIS and Law and Order variants. Each has their own flawed characters. (Note that the show Monk is, as I would consider it, mostly a police procedural too. The entire premise of that show is that Monk’s phobias let him see the details that other people miss. Similar to Columbo actually.)
*I used many shows from the 1970s as that was the decade that shows started the trend toward realism. 1960s shows like The Avengers and Batman have their degree of procedural-ness but were hyper-stylized. Basically, they are super heroes. Literally in the case of Batman.