And we did. We got Ravana's theme (which people apparently hated for some reason. I love it), Singularity Reactors theme and the new final boss theme for most dungeons. If everything were orchestral, the game would sound pretty bland. To go further back, there's Shiva's phase 1 theme, Ramuh's song, etc.
It's kinda like Bayonetta. You have your amazing orchestral music in places, but there's also the jumpy and motivating pop/club-music. It gives the game extra spice.
