Having Bolin use some Lava-Bending would be a lot more interesting. Could set him apart from Lin and some of the other EarthBenders. I think it could go either way though. Now that I think of it, Bolin and Mako have both Earth Kingdom and Fire Nation blood in them, and Lava is seen as a Fire+Earth power.
Did they say if that Lava-Bender(sorry forgot his name)was mixed too? Maybe that's how he can use his power.
Tenzin's fight scene was really good. Nice to see what he might really capable of.
Ghazan doesn't look like a combination of Fire and Earth Nation. He strictly looks Earth. And like I said, given Bolin's zero understanding of how to even start learning lava bending, it would be a total deus ex, and I hope it doesn't happen. If anything, I'd prefer him discover some awesome Earth bending technique (on accident).
I wasn't a fan of the first half of the episode, but holy crap the second part was awesome. I hated the fact some people considered Zaheer to be on equal footing with Tenzin. Well this episode debunked that. Kya just got owned hard. Bumi had better results against Ghazan lol.
I do anticipate Korra to get captured/traded in as a hostage in order to explain the RL reason for wanting her. If that doesn't get explained along with Guru what's his face...I mean...that would just be bad writing lol.
Also, Jinora once again being useless. I hope she steps up big time in a more reasonable way compared to Book 2.
Slight spoiler ahead. Source comes from SDCC trailer...
There is still a screen cap floating around of Tenzin doing a jump on some flat side of a mountain. This picture matches the SDCC footage of Lin fighting Zaheer. Tenzin will be free'd, but we don't know his fate afterwards let alone his current condition.