With Kingdom Hearts I.5 HD Remix out and II.5 HD Remix on the way next year, there's nothing left to re-tell as we prepare for the eventual release of Kingdom Hearts III. Oh wait, yes there is.
The HD collections of the Kingdom Hearts saga currently cover every previously released console game in the series except for Kingdom Hearts 3D [Dream Drop Distance]. Asked about it in an interview with Weekly Famitsu, series director Tetsuya Nomura replied, "The HD remastered games are a summary leading up to KH III. It'd be sad for one chapter not to be in HD in remaking the series, plus KH3D is a necessary piece for telling the story of KH III, so I've been telling myself that we need to start considering it."