I thought the finale was really good. At first it didn't seem like much was happening, and it looked like the writers chickened out again when Quinn didn't go through with his mission. But then... wow
. They even killed one of the shows main characters.
I believe Brody for the time being, because in the past he has seemed to be against the idea of killing civilians.
There is a bizarre theory over at the IMDB.com forums:
Brody definitely had nothing to do with the explosion, he seemed content with the direction his life was taking - he was free of Abu Nazir, Walden was dead, he left his wife and was ready to start a relationship with Carrie ...