It took me a while to figure out my exact problem but it's this: Joss has given in to nihilism. It'd be interesting to go back and re-listen to his Harvard talk on Humanistic Atheism, where he tries to affirm that value can be found in a godless world. But in Cabin, well -- it had to end the way it did; but that begs the question of just why we should get out of bed every morning. It'll be interesting to see how that plays out in the plotting for season 9.
Anyway, in case you couldn't tell: Cabin in the Woods -- clever, for sure. Well done and thought-provoking in all the ways Max says. I despised it.
(And when exactly did it get so expensive to go to the movies?)