I rewatched yesterday, and the scene that caught my attention is when Dean's in the car with Castiel. Castiel says that if he changes things, then all the people they save will die, and Dean says he cares a lot, but this is his family. Because your commentary about this week's Sarah Connor Chronicles was all about the one versus the many, I thought, "That's it. That's the test." Maybe it was only partly about giving Dean information and partly about testing him to see what he'll do when given the choice. I wouldn't be surprised if the angels were hoping his time in hell would have changed him enough to choose the world over Sam this time around.