I would like to see Anna again, and I would like to see michael get an "improvised" vessel, much like Lucifer did, just to see him make his own case to Dean as to why he should say yes. Right now, Michael is just this completely off stage force that has no real identity.

I really like the actor who is playing Lucifer right now - he he's subtle, fatalistic, and funny.

I did like the kids who played Sam & Dean in "After School Special", but I don't really know what flashbacks would contribute to the story at this point. I think the selection of Sam & Dean as the vessels is just one of those "destiny" things.

Dean should never, EVER, lose the Impala.

Castiel's arc has been good for me so far - he's gone rogue, helped the Winchesters in their plan to kill the Devil, been tempted by the Devil, and is (very slowly) warming up to Sam. I can fully understand his reluctance to like/trust Sam, and any warmth between the two would just be forced and contrived.

You think Dean is ManPaining now? Did you not see the entire season where he *cried* about torturing people in Hell?? At least he's a bit more focused now... Besides, there's nothing wrong with a little ManPain, it keeps some personal angst in play.