Because, let's face it, we all want one. To stay Canon, it would have to be based during the Keyblade War, and have little to no mention of current Kingdom Hearts characters. The game would be heavily PvP, or, Player vs. Player, based, and there would be the two obvious factions, Light, and Dark. All characters would start out as Level 1 Keyblade Apprentices, then, based on how you put your stats and what abilities/commands you pick, you would get your Class and role in combat. Light and Dark would have different titles for the same classes, and exclusive moves to each side, and exclusive moves to each class. Weaponry would be your keyblade, which would evolve with passing experiences, or simply stay the same and get stronger as you leveled. Armor would be earned, melded, or dropped, depending on its class and strength. For example, high level armor for Dark Knights would be the same dark armor that Vanitas and Riku wore, having to be earned from a certain mission. More ideas to come, but let me know your opinions. (: