Here's just another opinion thread...
As we all know, Ozai has taken a backseat to every other character. This is caused, obviouly, by his extreme lack of screentime, along with the constant development of Azula. Even though he's the True Villain of the series, many fans proably don't view him as a huge threat... (he's in the crappy, secondary/supporting character section on the Avatar Wikipedia page)
Personally, just because of the sheer mystery around him, I think he's a pretty awesome villain. And yet, in the trailer, we see Aang deflecting normal, orange fire. This leads me to believe, that the finale, Ozai's epicness will once again be shafted for Azula-time. Either that, or the natural disaster of the Comet crashing will overshadow him.
I just want some opinions of Ozai, and what you're expecting from him.