A very, very fine line to walk on since comic fans can be one of the most rabid fan bases to appease. Very similar to hardcore fan bases of sports teams.
Agents of SHIELD has had its good moments and its bad moments. However, its ratings are beginning to maintain a general stance in the weekly rankings to the point where the website TV By The Numbers has SHIELD trending to get renewed for a second season.
Regardless of what you loved (or hated) about Agent Coulson's death reveal in the mid-season premiere or the "Thor: The Dark World crossover episode" which was more of a reference than a crossover or the introduction of Deathlok into the series, most viewers seem to like the show. Also, it will help when the show brings in actor Bill Paxton in upcoming episodes and having a crossover with Captain America: The Winter Soldier at the end of its first season will also help increase interest in the show.
Not everyone likes the show though, and this is just the opinion of The Daily SuperHero so don't take this as fact, but a SHIELD movie should have been done instead of a TV series. It could have starred Coulson, Nick Fury, Hawkeye, Black Widow and Maria Hill. Who wouldn't want to see that on the big screen?
Bottom line, it seems like Agents of SHIELD could be getting a season 2 green lit soon if TV By The Numbers' projection is correct. A second season—that would probably air this fall, if green lit soon—could help lead up into Marvel's next big ensemble movie in May 2015 with Avengers: Age of Ultron.