>People actually think there's going to be a Z instead of an XZ and a YZ
Let's talk about why said people are idiots.

>Money
Gamefreak and Nintendo both really like money, almost as much as they love screwing over other countries besides Japan.
If they sell an XZ and a YZ, They can potentially make way more money than a single version.

>Lysandre
The third games in all of the series tend to have very similar plotlines and are never sequels. At the end of X/Y, Lysandre is "killed".
Think about that for a moment. There's no way they'd just kill of Lysandre. So, they're going to go B/W2 style and make sequels.

>Precedent
They've started a precedent for making 2 more games. There's no reason why they should stop.

>There are two more games that we know of for gen 6
This one is off the top of my head, but I remember reading more than once around here that there were 6 Gen 6 games found to be compatible with Pokébank or some shit like that, 4 of which are obviously known already. It would fit for there to be an XZ/YZ.
If someone could explain this so I don't seem like a nutjob, I'd appreciate it.