I see a lot of people saying that they would rather KH not system jump anymore and just keep it to one console. I agree with the no more system jump thing, but I think all of the games should have been spread out throughout other consoles. If KHIII is going to be multi-platform, then the ReMIX's should have been multi-platform as well with PS3 and Xbox 360. I also think they should have included Vita, because Vita will play a vital part in the PS4's lifespan with Remote Play and people who bought the ReMIX's for the Vita could get KHIII for the PS4 and remote play on it. It would have done nothing but brought up sales and could have brought up KHIII's Xbox sales way more than I predict It's going to sell.
In response to the OP, I don't see 2.5 coming to Vita unfortunately since 1.5 wasn't released for the Vita.