Tarrlok is defeated!
So today's episode, "Out of the Past", definitely answered a lot of questions that were on people's minds. Once again I am impressed by the collective ability of the fandom to come up with the correct theories about Yakone and his connection to Tarrlok, as well as Tarrlok's motivations. Seeing as how Amon took away Tarrlok's bending, I'm inclined to believe that the two of them were not in cahoots with each other. Technically the possibility still remains that they were formerly partners and ended up betraying each other (it would explain how Amon was able to find Tarrlok so easily), but having seen the trailer of the season finale and how the Equalists appear to have the upper hand, it seems unlikely that Tarrlok would intentionally strengthen the Equalists to gain more power. For a crafty politician like him, he probably would not have taken such a huge risk to get what he wants. One question that hasn't been answered yet is how someone can bloodbend without a full moon. We know that Tarrlok learned this from Yakone, but how did Yakone acquire this ability?
What's up with Amon??
One thing that makes me wonder is Korra's vision of Aang's encounter with Yakone. It makes sense why Aang would want to warn Korra about Tarrlok, but why hasn't he given her any help or insight with regards to Amon? Amon clearly seems to be the more dangerous of the two. There are two possibilities that I can think of:
1) Aang is trying to tell Korra that she needs to deal with Tarrlok first before figuring out how to deal with Amon.
2) Even Aang does not have any advice that is directly relevant to defeating Amon. Since Aang had to be taught to Energybend by the lion turtle, it makes sense if even Aang does not know how Amon got his ability.
Personally, I would opt for number 2. After seeing Amon shrug off Tarrlok's bloodbending with little effort, this leads me to believe that there is something almost inhuman about Amon. Even Aang had to go into the Avatar state to overcome Yakone's bloodbending (and it was Katara's mastery of waterbending that allowed her to overcome Hama's bloodbending), so even if Amon cannot bend the elements, he at least has some sort of "bending" ability that allows him to overcome Tarrlok. I previously believed that Amon was simply lying about the fact that the spirits had chosen him to bring equality and that his "energybending" was nothing more than advanced chi-blocking. Now I'm not so sure. Since Koh the Face-Stealer appear to be a kind of malicious or even "evil" spirit, it may be possible that there are many other evil spirits who want to destroy the Avatar and remove bending from the physical world.
The Season Finale promo
The scenes shown in the promo were "explosive", to say the least. Clearly there is some kind of full scale war going on, with aircraft dropping bombs on ships. At this point I'm assuming that the planes belong to the Equalists, since the planes seem to have the Equalist logo (with the character "平") on the wings. There are also a few brief scenes in which it looks like (at least to me, anyway) the Equalists have taken over Air Temple island, and metalbending cops (or maybe they are task force members or soldiers, because the uniforms look slightly different) and White Lotus members are being lined up to have their bending taken away by Amon. If I were to guess what is going to happen, the Equalists manage to gain control of Republic City, which prompts the navy of the United Republic of Nations to deploy their ships to take back Republic City. Right now it's looking very likely that the Equalists are able to use their planes to defeat the navy. Originally I was thinking that Korra would be able to defeat Amon by the end of this season. But now that I've been reminded that book 2 of ATLA ended in a decisive defeat for Aang and his friends, I'm starting to think that the something similar will happen to Korra. Possibly she will go into the Avatar state and escape from Amon's clutches, but will be forced to flee from Republic City along with Tenzin (and family), Lin, and the rest of Team Avatar. It's kind of distressing to consider such a bleak possibility, but it makes sense as a way to ensure that the viewers will be back for season two.