This episode sums up everything that has been hinted since the beginning of the season, reinforcing several plot points while expounding on a few others. Reaction to the episode will vary depending on interpretation of information already available. For example, if the clues regarding the relationship between Sam and Ruby were overlooked amidst the mystery of Dean's restoration, then the confirmation of their physical acrobatics. (To be honest, I was a little disappointed by the fact that Ruby wasn't still played by Katie Cassidy in those moments.)
One might argue that Sam would justify his decision to hone his psychic powers because of the immediate benefits; the hosts are saved and the demons are sent back to Hell. But Sam's reasons were not that noble. He's also willing to sleep with Ruby, despite the fact that Ruby is essentially controlling someone else's body. Does it mitigate the question of consent? The disturbing connotations serves to underscore the fact that Ruby is, in the end, still a demon.
Ruby has always wanted Sam in this position (or why bother inhabiting a hot young woman in the first place?). Ruby represents a quickly diminishing minority among the demons who still look to Sam as the Antichrist Superstar. The fact that Ruby saved Sam's life on more than one occasion doesn't erase the possibility of an ulterior motive.
The other side to this episode was the more immediate problem of Anna Milton. Anna reveals that Lilith's gambit is a lot harder to counter than originally thought. In fact, it clarifies the reason for Castiel's worry over the progress of the war. If Lilith had a specific list of 66 seals to open to release Lucifer, the tactics would be very simple (if incredibly harsh). Set up the best angels to protect a handful of seals, and Lilith could open the rest without achieving her goal. Thousands of people might die, but one could still consider the mission a success.
But the true situation, thanks to a clever interpretation of the Revelation, is far more complex. There are about 600 potential seals, and only 66 need to be opened for Lilith to win the day. (See what they did there? Six hundred, and sixty-six.) Unless there is an artificial timeline waiting in the wings, Lilith can bide her time and wear down the opposition.
ThatÃ¢â¬â¢s an important consideration, because it gives a definitive reason for why Castiel and Uriel would come calling for Anna. The demons would want Anna because she is the perfect means of gaining more advantage over the angels. Anna must die, and who better to deliver that fate than the angels of the Lord?
I think some fans might be balking at the depiction of the angels, but I find it refreshing. Popular culture depicts angels as uniformly compassionate, nurturing, and, ultimately, rather impotent. They only seem to intervene in positive ways. Angels in open war to prevent an apocalyptic maelstrom would no doubt be more like the imposing and implacable figures of old.
So what about this case? It's not known why Anna has the ability to tune into angel radio, but she can. That ability stands as a threat to the world. So, in this case, Anna must die. I don't see this as a further bastardization of the depiction of angels, because this could simply be a case where we get a glimpse of what normally is unseen. The real question is how the Brothers Winchester will react to that directive. Something tells me they're not going to accept the whole "because God said so" explanation. (Especially since Dean is clearly attracted to Anna.)
Whatever the case, this is a serious situation, because we now know that there are demons out there beyond Sam's ability to exorcise and immune to the Magic Knife. Something is going to have to give, and it's not going to be pretty.