I'll definitely fight you on that!!!! First of all, I definitely think you're wrong on it being Katara who takes Azula down - that's definetly going to be Zuko. Granted, Katara may be present at it, but even if she is, I have a hunch that Zuko will tell her not to interfere, so he can challenge Azula to an Agni Kai. There has been way, way too much foreshadowing of of a final Zuko vs Azula showdown for the writers to chuck Zuko out of it and let Katara do it. You mentioned bloodbending, but the finale is probably going to take place during the day, when Katara can't bloodbend even if there was a full moon. Also on the subject of blloodbending I think that the most likely time for Katara to use bloodbending will be during 316 - The Southern Raiders, which will probably be when she oes on that ninja mission with Zuko. Granted, there was a clip in the trailer that showed Katara getting away from an absolutely massive pillar of blue flame that must have originated from Azula, but from examining her surroundings I'd say that this confirms the theory that Azula will somehow find the gaang at the end of The Emeral Island Players, and there will be a brief skirmish before they escape. If you want clinching proof, the recently released summary for Into the Inferno says that Zuko is going to confront his sister in that episode.

For your comment about stereotypical endings, I'd like to ask you if you thought that Season 1 had a stereotypical ending. The bad guy died, with his plans having come to nothing, his army was obliterated, the good guys had triumphed, etc, etc, and yet it did no feel like a stereotypical ending. We always knew that the heroes of the story will win out in the end, and by definition that means the villains lose, but personally I don't mind this as long as they are allowed to depart with respect, basically doing some damage on the way out. Bryke have shown that they care deeply about their story, including the villains, and this has been reflected in both the character development those villains have recieved (a very rare thing), and the fact that when those villains lose, it is never in an expected way. Very few people when watching the episodes for the first time would have been able to predict that Zhao would dragged underwater by the spirit of the ocean, that Katara would summon up the will to bloodbend Hama, that Combustion man would blow himself apart, or that Ty Lee, of all people would turn on Azula.

Falling in love (figurtively or literally speaking, whichever suits you) with the villains of any story always has the sad result of seeing your favorite characters go down, and with a show like Avatar that allows you to love (or love to hate) those villain(s) so well it is especially painful. But as long as Bryke and the writers maintain the great story telling, ability to pull suprising twists and respect for their characters that they have exemplified thus far, I will be happy when Azula and Ozai meet their ends. Either way, I have seen nothing in any of the trailers released so far to indicate anything other than the final episodes and the finale being so epic my sense of hype will not even begin to fade until the dvd is released, at which point I will watch it again, and probably die of epic overdose.