I thought the whole series was going to be this apocolyptic storyline with Moloch, and there are tons of other demons, and figured we would be getting a hierchy of evil with 4 horsemen, and each season would build on a bigger storyline, like a different take on what Supernatural did. The first season's twists were well done and organically laced together. Unfortunately, it doesn't sound like they ever had more then 1 year of stories in mind....
As I recall, they didn't get rid of Moloch until midway through season 2. I wonder if that was a change imposed by network meddling, like how Alias abruptly wrapped up its defining SD-6 arc midway through its second season, flailed around for the rest of the season, rebooted with a new story arc that defined season 3, then wrapped that up and re-rebooted in season 4 with the characters joining a new organization. Wow, that's uncannily similar in some ways -- although Alias at least kept most of its cast intact from season to season.