It looks like you’ll soon be able to play as any of Final Fantasy XV’s lead characters, with the option to switch between Noctis, Prompto, Ignis and Gladiolus at any time during the game’s story. In an Active Time Report Special held on the official Japanese Square Enix YouTube channel, the dev revealed the new feature coming soon.
Potentially, you could clear the game with Prompto, Ignis or Gladio if you wanted to, as stated in a summary and translation of the stream on Reddit. The only caveat is that you obviously can’t play as characters absent from your party, but you do have full control over each character when playing as them.
Hardware issues apparently meant that this feature wasn’t feasible until now, according to Square Enix, with character swapping seemingly set to arrive ahead of the Episode Ignis expansion on 13th December. Potentially, quite soon then. There’s also more to come to Final Fantasy XV in various updates soon, including loading time reductions, bug fixes and so on.