Square Enix continues to cater to those strange fans that like Lightning so much that they want another FFXIII game. That's why FFvXIII is on the back burner and therefore why KHIII is on the back burner.
Jessie Mccartney, the voice actor for Roxas, tweeted and posted pictures of him recording for this game recently, so I'd say it's got great chances of coming westward.