I'm gonna back up Azmodon here. When CoTM was fist released, it was well praised by both fans and game critics alike for its music, but, as admitted by the developers at the time, in order to free up space for the tunes, they had to sacrifice visuals. Circle, and this is my subjective opinion here, has the worst visual presentation in the franchise outside the Gameboy games. It looks like a first generation Sega Genesis game: dull, murky, and wooden.
When it came to Harmony, then, the developers took the criticism of the visuals to heart (remember this was when the Game Boy Advance lacked a backlit screen, making a dark, uncolorful game extremely difficult to see unless you happen to be in the perfect light) and flipped the aesthetic, sacrificing the music for better, more fluid and easier to see visuals.
Arguably, Aria of Sorrow is where they finally found a comfortable balance between the two, featuring both detailed, colorful visuals and a respectable score. I had hoped that Order of Ecclesia would follow a similar trajectory, and be the most refined entry on the DS as AoS was on the GBA, but thusfar, I'm unimpressed.