>>25283445Niji or Rainbow or whatever the fuck you want to call it is a damn codename at this point. It is also the 20th anniversary title. There is no way in hell that this is going to be the third version of XY. That will be a separate release. This is bound to be something different in celebration of 20 years, and there's just no possible way that that can be done properly in a third version that's locked into a particular type of storyline already.
I have no idea what they're planning with it, but I'm personally hoping that it's a mainline type of game that simply does something special to celebrate, like give us some kind of alternate universe region to explore that features gym leaders from all the generations/regions so far and a unique and diverse selection of wild pokemon plus a bunch of fun extra features, like following pokemon, trainer customization, contests, etc. all in one package. Complete pipe dream and it's almost zero chance of happening, because Gamefreak apparently don't understand that they could make billions if they'd just give us what we've been asking for all these years, but it's still fun to think about from time to time.