Well, kroki_refur's review (http://kroki-refur.livejournal.com/234013.html#cutid1) this week addresses the lack of Sam-focus in some detail. (Her review this week is less funny and more ranty than normal, but still enjoyable). I'm not sure I entirely agree--there were several episodes that seemed pretty focused on Sam to me, especially Mystery Spot and Fresh Blood--but it's true that while the central dilemma of S2 was Sam's mysterious fate as a special child, the central dilemma of S3 was Dean's deal, so that's definitely a shift. I'm still seeing the past few eps as the aftermath of Dean's deal, though--I expect once the angel v. demon war gets going we'll see more Sam.

I wondered what happened to the demons, too--and also their HOST BODIES. Because if the Colt and the magic knife kills a demon out of existence, wouldn't it do the same thing to the poor human meatsuit?