So I finally got to play the game on a surround sound system. The battle theme really, really comes alive in surround. I already thought it was absolutely superb, but the mixing really makes it a legendary battle theme that I am pretty sure is going to be remembered for a very long time. It's so game-appropriate...it has this big boastful sound to start, but the entire song is kind of infected with this twinge of sadness, of tiredness-- you can kind of feel Kaim's general apathy and disappointment with life and battle in general.
It's not overproduced or sampled poorly like FFX's battle theme, and it doesn't really evoke any nostalgic feeling for any of the older Final Fantasies. To me it's just a completely original, well composed, well sampled piece that is simultaneously haunting and encouraging.
It's really, really beautiful.