And that's exactly why it's the best thing that could have happened to The Walking Dead.

The Walking Dead was last year's breakout TV hit. It earned dozens of glowing critical reviews, netted AMC its best-ever ratings, and - perhaps most significantly - became the most-viewed basic cable drama series of all time in the coveted 18-49 age demographic.

It has also, unexpectedly, become the lynchpin of AMC's original drama lineup. Fellow freshman series The Killing alienated its viewers with a disappointing season finale. Mad Men's fifth season premiere was delayed until 2012. Hell on Wheels, a period drama that debuts later this year, remains an unknown quantity. Breaking Bad carries significant critical cache—and earned series-best ratings with its season 4 premiere—but lacks The Walking Dead's broader appeal. Now more than ever, AMC needs The Walking Dead to bolster its newly-earned reputation as the channel for viewers who want quality dramatic television.

When I reviewed The Walking Dead series premiere last October, I gave Frank Darabont the majority of the credit for the series' stunning pilot episode, "Days Gone Bye." The two-hour premiere episode is one of the best pilots I've ever seen. From the opening scene of "Days Gone Bye", Darabont's meticulous direction imbues the post-apocalyptic world with a texture and scope that rivals anything seen in a movie theater.

But the rest of the series' first season—while generally entertaining—never came close to the quality of "Days Gone Bye." And just as Darabont deserves much of the credit for the series' initial success, he deserves much of the blame for the series' later failures. Darabont wroteThe Walking Dead's disappointing second episode, " Guts," which featured the series' biggest (and most irritating) deviation from the original comic books: the introduction of cartoonish villain Merle Dixon. And Darabont co-wrote the season finale, " TS-19"—another silly departure from the comics, and another misstep for the fledgling television series.

To be fair, Darabont deserves a lot of credit for getting The Walking Dead onto television at all. After discovering the comic series in 2005, he spent five years working on adapting and producing The Walking Dead. Three of the show's major actors—Jeffrey DeMunn, Laurie Holden, and Melissa McBride—appeared in Darabont's 2007 adaptation of Stephen King's The Mist, and it's a fairly safe bet that Darabont had a hand in recruiting them for their roles on The Walking Dead. Just by being attached to The Walking Dead, Darabont gave it extra credibility; early promotional posters advertised the series as "from the director of The Shawshank Redemption."

Ironically enough, the advertisement speaks to Darabont's biggest hurdle: He's a film director. "Days Gone Bye" was so effective because Darabont directed it like a movie, with a length and a production design to match. But Darabont has never worked in television before, and when it came time to turn his two-hour pilot into an ongoing series, he faltered. The Walking Dead has always needed a television-savvy hand to guide it. And fortunately for AMC, newly appointed showrunner Glen Mazzara is much more qualified than Darabont for the job.