I have the dungeon, what I can't get is the difficulty unlock like the PS2 version. New File+ = Unknown unlocked. Old save file = Hard and that's it.I'm pretty sure the difficulty still unlocks the same, but I don't know about the ex dungeon. Maybe you missed the sidequest that opens it? I don't know why they would change this considering how little else they changed.
On a more related note, Expiation is absolutely glorious. I never get tired of seeing it.
Cheria's Trillion Drive for me. Love the sound effects, graphics and animation, and Cheria's speech.