Helpful hint: if, like me, you were thinking of downloading the last episode of this season so you don't have to watch it with your MIL do not put 'Homeland Season 3' into google. Some US websites have very spoilery titles to their links.
My lips are obviously sealed though. (And I haven't actually watched the finale because I couldn't see a link which didn't look likely to give me a virus.)
Re the last episode, I'm pretty sure that Brody hadn't actually turned once again on his increasingly tiny fulcrum, because Carrie said he hadn't and she's always right yes? I think he knows that there is no way out for him, in terms of rehabilitation by the CIA unless he goes through with his mission, so he was playing the long game and that's why he refused the offer of extraction. Also, it's supposed to be about him redeeming himself, he has to go through with it or he is still just the man who put on that vest.
I did think the that the episode was very rushed though. In terms of the season as a whole, they could have spent a lot less if it on Dana's Creek and a lot more of it on Brody's time in Iran. There was, for example, no explanation of how Carrie had persuaded Saul to let her be in charge of the mission on the ground (though possibly because any explanation would be entirely implausible).
I really liked the scene between Brody and Abu Nazir's wife though. Even though Brody ultimately hadn't bought into the cause, there was genuine emotion there when they discussed what they had lost and how they had to emerge from the rubble and keep on going. And I thought the ending was great, Brody goading Akbari into admitting that he was just a pawn all along, which then justified to him the decision to do him in.