Warning: Spoiler Alert
I really wish that it hadn't been kind of obvious that Ellie had made a deal with Crowley, but it was. And I suppose that things can't always work out where you (as the viewer) can't guess what's going on with at least some of the things that are happening with any given episode (or the mythos in general).
I can really appreciate the fact that Dean wants to protect her from Crowley and the hellhounds that he's bound to keep sending after her to get her soul, but regardless of how good his intentions are ... Sam has a point. At a certain point, Crowley (or one of the mountains of hellhounds he's going to send after her) is going to find her, and she's going to get dragged into the Pit. There isn't any way around that ... unless Kevin and the boys are able to figure out a way to close up Hell forever (and send all of the Earth-bound demons back there) so that no human is going to be able to be hurt by a demon ever again. There are a couple of problems that I see with that. 1) Show has been renewed for a ninth season, and I don't see the writers going back to dealing with folklore the way they did in season one. At this point, angels and demons have become the bread and butter of the show (even if I would love it if the writers stopped focusing almost exclusively on Christianity, and went back to folklore from all over the place, the way that it was in the beginning). 2) Just cuz Kevin and the boys might be able to rid the world of demons and angels for the rest of eternity, that doesn't mean that Heaven and Hell are closed to humans after they die. At no point did Kevin say that the tablets that he's read have said that humans would need to find somewhere new to go after they shuffle of the mortal coil, just cuz they have stopped humans being generally harassed by spiritual beings out of the Christian mythos system. So, she might get a few more years of life, but Crowley still holds a contract that says that she is his bitch. It would be kind of an interesting twist if cuz of the fine print of the tablets, if/when the gates of Heaven and Hell are sealed forever, anyone who is still alive who made a deal with a crossroads demon is allowed to go to Heaven (as though cuz they were able to stay alive until "time ran out" for the demons' free reign on earth, all contracts that still have not been collected at this point are null and void).
Also, I don't think I like the idea of them being able to see hellhounds (even if they have to use the magic angel oil to do so). Part of what makes the hellhounds fab is that you don't see them; they come at you, and the only warning that you have is the howling and (possibly) the destruction of property. Other than that, you really have no idea of exactly where they are, and they could be far closer to you than you realize. That would make them a bit more frightening, IMO, and stripping that away from them takes away some of the horror and the "magic" from them.
The fact that Mary became kind of a "thing" in this episode (what with her picture being put up in what is now Dean's room, and Ellie referencing her), makes me wish even more that the writers would finally let us know what happened to her and to Papa. There was that whole thing in season six with the mother of all monsters, and the inclusion of the Campbells, which would make you think that maybe (just maybe) we would be getting some answers about what the hell happened to Mary ... especially since Samuel made it sound like he knew where she was. It was very true that Crowley could have been yanking Samuel's chain so that he could get what he wanted from the guy, but whether or not he was was never answered. Whether Samuel actually knew where she was, or if Crowley was only trying to use him was one of those things that was just left hanging. And if they're going to keep bringing her up, it would be nice if we finally had some kind of answers as to what was going on.