7) Did the lack of Supernatural elements in this episode - and the resulting reliance on character and dialogue - help or hinder it? Why?
Bardicvoice: For this story, I thought the Mark of Cain was a sufficient supernatural adversary. I'm actually glad there wasn't another supernatural component, because for me, that would have diluted the story's emphasis on humanity and family. I don't think it worked as well as it might have because so many stories were shoe-horned into too small a space, but I believe having a monster story in the mix would just have muddied the waters even more.
Nate: I would disagree that this episode lacked supernatural elements as its main focus is the quest of a “monster” [angel] to make amends for the wrongs it has done to others. While it is Castiel and we may forget that he’s not human sometimes (especially since he is human once in a while) it doesn’t change the fundamentals, and that he must struggle to accomplish something that humans know almost instinctively. While true nobody’s born a parent, and we all have to struggle to be one, Castiel’s story is a chance to highlight things we take for granted by being human beings. I would like to see him bring Claire to the Bunker so we could get “3 men and a little lady” shenanigans for a time.
Pragmatic Dreamer: Except for Mark of Cain turning Dean into a Psycho Natural-Born Killer. And Claire seeing the Angel who possessed her & killed her father. I didn't miss an overt Monster. Randy & the Good (bad) Fellas made for an interesting human-as-monster comparison.
The near-rape bothered me because it's too much like real-life. Big topic of discussion here in Canada & the US right now. Watching that scene I was acutely aware that an incident like that was likely playing out in real time somewhere and the tragedy is there wouldn't be any Winchesters coming to the rescue.
Metamorphic Rocks: Supernatural had another episode that was entirely about human actions in "The Benders," so this episode followed in a similar vein. However, "The Benders" had far superior characters and dialogue. The Bender family was truly scary, and the police officer Dean interacted with was strong and complex (very much like Jody!), even for a one-off guest. That episode proved that powerful characterization and gripping dialogue can be just as compelling as cool action sequences or creepy supernatural elements. With "The Things we left Behind," I was initially very curious to see what became of Claire, but I thought her character trope was very overused (rebellious teen with a heart of gold), and the dialogue between her and Castiel was mostly just average. The brothers got very little dialogue (with the exception of the John Winchester story), so we didn't get any new character beats from them. Regarding Rowena, she has the potential to be a fun character, but right now she isn't doing much of anything - actually the same can be said for Crowley, who is an interesting, multi-layered character and even gets great dialogue, but just isn't being used effectively right now. And listening to the stilted dialogue of the other demons around Crowley is actually painful. They need to move the King of Hell out of that warehouse (or wherever they are).
So, the reliance on character and dialogue certainly didn't have to hinder this episode, but because it was all average, it did. The last five minutes of Dean's massacre of the criminals was needed to infuse the episode with a little excitement. Like a bland meal, it needed something more to spice it up.