Can't understand this to be honest, its like they were forced into bringing it back, but set out to make sure it couldn't possibly succeed:
Dramatically cut funding. No more big open space scenes possible, lots of small, crude sets.
Purposefully leaked the first 3 episodes way early. CBS knew that most of the fans of Jericho would watch them online, and that, if put out on the net early enough, casual viewers would watch them too. There's an instant, large ratings hit for the first 3 episodes of the show.
Only gave them 7 new episodes. What can you do in 7 episodes? everything gets squashed and compacted, there's no detail. While the episodes have been gripping, there's been too much going on in some of them, and things generally seem hashed together.
Strange by CBS, you can really tell they wanted it to fail.