As for the sneak peeks everyone seems to be freaking out about, I'm actually not that worried about it? With all the interviews and general overview of what this season is going to be exploring, I'm mostly neutral and optimistic about where the story direction is heading. Every character is going to be going through something, giving their arcs some individual attention separately from one another and yes, that means some of them will go through the wringer because of it. But I'm positive all will come together by the end of the season regardless. Besides, Carver has already stated a while back that nothing is what it appears to be, which means that what happened in Purgatory, and in turn what happened to Castiel, is going to be the mystery that will be gradually revealed for at least the first half of the season.
Aside from that, I'm also very pleased with the casting of the new group of characters that will be introduced this season, particularly with the new angel. Now that was a pleasant surprise I didn't see coming.