My argument isn’t that Aang didn’t see the killing directly, it’s that he was possessed by a very powerful and angry spirit, so he didn’t have control over his actions.
Also, Aang managed to achieve the same effect - arguably an even more positive one - by not killing Ozai. Sure, killing him would have been simpler, but the show directly shows us that it would not have been better.
My argument isn’t that Aang didn’t see the killing directly, it’s that he was possessed by a very powerful and angry spirit, so he didn’t have control over his actions.
Also, Aang managed to achieve the same effect - arguably an even more positive one - by not killing Ozai. Sure, killing him would have been simpler, but the show directly shows us that it would not have been better.