I was thinking that as an post-game option, you go to place where you can fight other Keyblade Wielders (both good & evil) in the game and you can choose who you can play as. It's almost like the Olympus Coliseum but without the heartless/nobodies. Each round, you fight a wielder and at the last round will be a boss that will hint at KH4 and will give you the Ultima Weapon. Then there's another option where you fight their Keyblade Armor which is harder and gives you another Keyblade stronger than the Ultima Weapon!
I was thinking that as an post-game option, you go to place where you can fight other Keyblade Wielders (both good & evil) in the game and you can choose who you can play as. It's almost like the Olympus Coliseum but without the heartless/nobodies. Each round, you fight a wielder and at the last round will be a boss that will hint at KH4 and will give you the Ultima Weapon. Then there's another option where you fight their Keyblade Armor which is harder and gives you another Keyblade stronger than the Ultima Weapon!