Does anyone else think that the Sun logo is deliberately designed to look like the letter X? The Moon looks like a sickle, which in turn looks like the letter Y... Okay that may be a stretch. It looks like a C. But let's just say it can look a bit like Y.
I think this may be a hint that backs up many's expectations that these Gen 7 games will be the continuation of the Kalos games, X and Y. Maybe the mascot legendaries will be an upgrade of Xerneas and Yveltal in the vein of Mega Evolution or Primal Reversion. I think this route makes sense to me, especially since Sun/Moon has supplanted Z, because:
- The games can be reasonably expected to feature Zygarde pretty heavily. The reveal for Zygarde suggests that with its many formes starting from a weak core to a moderately powerful serpent to a titan-like winged dragon implies that you will be nursing it throughout the game to let it achieve its full potential.
- Following that, the threats in the new games must be something that specifically Zygarde alone can handle. With Zygarde being said to monitor the balance of the Kalos ecosystem, the threats have to also be relevant to the Kalos region. Not that external or new threats are inconceivable, but the ultimate weapon and Xerneas/Yveltal is possibly the deadliest mess in the history of Kalos.
- Zygarde's abilitiy/theme is also designed to be the antithesis of Xerneas/Yveltal, with Aura Break somewhat countering the two mascots in the lore. If Xerneas/Yveltal are not involved, the only ways to make Zygarde a relevant solution to the threat is by introducing other Aura-exerting legendaries (highly unlikely) or giving Zygarde's new formes a new ability (more likely, but will make Aura Break look awkward on a 50% Zygarde).
- Xerneas'/Yveltal's reveal in XY was pretty underwhelming. Neither of them had the chance to showcase their full power, with them being revived and caught immediately... in a lab. This seems to imply that we have yet to see what the two are capable of in full.
- One of the first hints that we are getting two versions instead of Z was that the XYORAS game data allow for the Blue Pentagon mark to be applied to a Pokemon that is hatched or caught in XYORAS, and two more games. The Pentagon itself represents the shape of France/Kalos, and thus if Sun/Moon are the two games, the Kalos region should still be relevant as well.
- GameFreak seems to be cutting down on the number of legendaries; we went from the pretty legendary-heavy gens 4 and 5 to a generation six with only three in-game legendaries, and three event ones. If GameFreak wants to be as unpredictable as possible, reusing legendaries might be the way to do it.
- It even makes thematic sense, as Sun can be associated with life (Xerneas) and the sickle-like crescent moon with death (Yveltal).
So far, there are hints that there will be a new region (the NPCs in XY with their strange souvenir mumbo-jumbos), but my best guess is either that region is a continuation of Kalos under a different name, or that the new region will also feature part of Kalos a la Johto/Kanto.
Of course, this speculation relies heavily on the idea that Zygarde will feature in the next game in the way I think it is going to be logical to feature. Some have said that the Zygarde formes might be an anime-only exclusive, or a red herring in programming. But unlike the Azure Flute, the Zygarde formes are pretty heavily promoted through CoroCoro and a whole anime season. If I'm not mistaken, GameFreak has also never discarded the idea of fully-made Pokemon, i.e. Azure Flute may not be available, but Arceus has always been a thing.