An excerpt from Tim's interview with Creative Screenwriting:
Metaphors and Murder: Tim Minear on Reinventing Angel and The Inside BY JASON DAVIS
In handing the Angel characters the power of their former enemies, they discovered their metaphor. "Once you're out of college," showrunner Minear observes, "you go into the real working world to work for Greenpeace -- and now Shell Oil has offered you a job. Does it mean that you have to give up your values, or does it mean that you can actually apply your values to the thing that you thought was corrupt? That does seem like a metaphor."
While re-imagining Angel proved to be a case of focusing on an idea already present, Minear's work in bringing The Inside to television was a little more complicated. Often described as a twenty-first-century 21 Jump Street, The Inside had a lengthy development before Fox executives brought Minear onboard. The network executives "didn't necessarily want it to be a high school every week. They wanted Rebecca Locke [series lead Rachel Nichols] to go undercover every week.
"My feeling was that it's impossible -- you can't do that every week," responds Minear, detailing a common problem in the television industry. "When networks buy these show ideas, what they're really buying is an episode of a show. If the premise of the series itself sounds like it could be an episode of a show, it's probably not a series idea. CSI is a brilliant concept for a series, but it's not an episode of a show." According to Minear, the key to creating a television series is that "it's specific, but at the same time it's very broad."
I think you need to buy the magazine to read the rest (and the other article).