1. I am so sad that Erica Cerra's character is/was dead all along. I had a brief moment of hoping she'd be recurring. Recurringly awesome!
2. Cas was right! I wonder whether he would have listened to the humans about renouncing his power had they trusted him in the first place. Guess we'll never know given the Winchesters' ability to take any situation and make it worse!
3. For those looking for Sam/Castiel parallels, the fact that Cas blew up the first angel he encountered after getting pumped up past archangel strength was very Lucifer-like.
4. On the mindwipe, I have the following working theory: there's a guy, let's call him John for no reason whatsoever, in Lisa and Ben's memories, who had a fling with Lisa right before she got pregnant with Ben and who came back and saved Ben from a bad thing. Then he came back and after a good year things went bad. He convinced them to move but that wasn't good enough and they ended up parting, sad but understanding that it was the right thing for Lisa and Ben. Lisa and Ben haven't forgotten about salt lines, runes, or guns, only about a day of terror. The pictures Lisa keeps of that year have John in them.
This doesn't help at all with the part where Dean's request denies them agency and choice and all that fun stuff, I understand, but it limits the amount of explanation required for why they moved etc. so they won't be shocked when they try to go home, and also keeps them relatively safe, about as safe as they could be otherwise. Given that Castiel stepped up his advance planning game substantially in this episode, I am just presuming that he did so w/r/t Ben and Lisa as well. Further on safety: Let's face it, Crowley has other things to worry about, and it's not clear to me who else is left with a grudge against the Winchesters and the knowledge of what Lisa and Ben mean to them.