If they ever do it, I hope SquareEnix puts some honest to God
effort into any extra dungeons or features this time.
One idea I had is to create a dimensional gate in the Sea of Eden after clearing Chronopolis. Where does it lead? Viper Manor, or rather, another dimension's Viper Manor. Playing out the story of Radical Dreamers on the Cross engine, and dare I suggest a guest appearance by a guy in a mask?
Rewards could vary from small trinkets to maybe a secret character or two, but first and foremost I'd say a unique weapon for Kid is in order. She's one of the pivotal characters and she only has forged daggers? Rubbish!
Something opening up on the NG+ would be nice too. Perhaps a sprawling dungeon from a mysterious new door inside the Bend of Time?
The possibilities really are endless. I need to learn Japanese, move down to wherever Sqeenix HQ is, and make some of this happen.