I really do like the show, I wish HBO had produced it, as the content would have been infinitely less whiny and carried a good bit of maturity with it. I would have loved for it to have challenged my perceptions of religion and the true nature of humanity more than it tried to, but i don't personally see it as an indecent effort. And I do agree that one of the great things about the show is that it really doesn't take itself too seriously. They always have time to throw in a little bit of humor, both cheesey and brilliant, and I think it lends a more credible human element to the story. I liked the "real world" episode, when they end up on set as Jensen Ackles and Jared Padalecki and the story proceeds to lampoon the glamorized Hollywood way of life.
IT was supposed to end with season 5, but because the two mains were still under contract and ratings were still good, they ordered season 6. I think they did a decent job of finding a new route to take the show, but ultimately they are going to run out of good ideas, so I might be hoping that this is the last season.