EQ: What is the most important element in a successful Modern-Age comic book series?

Answer: An important element in creating a successful comic book series is to have a character that develops through the story.

Evidence/Source:
 - Evidence 1: Roy Harper is very well known within the comic book world and he's developed in his personal story in many ways. Staring off as a sidekick, he then became a junkie, then a father and when he lost his daughter, he went back into drugs. It's a natural progression of story that everyone who has read DC comics remembers.
 - Source 1: "Superhero Makeovers: Roy Harper" article.
 - Evidence 2: Even Superman has developed within the eighty years he's been around. The most obvious visual aspect of that change is his shield.
 - Source 2: "The Story of the Shield (aka Superman's Symbol 101)" by Brian G. Philbin.
 - Evidence 3: In the Modern-Age, people are looking for the humanity in comic books characters, and the best way to represent this humanity is to have them change through out a story or an event.
 - Source 3: Brad Munson, 3rd Interview.