Okay /vp/, long story short, I managed to get some info out of a disgruntled and drunk employee working for nintendo, and got some information on this gen's sequel game. I'm not entirely sure how credible this information is, considering how intoxicated he was, but it's as good as any.

1. They are titled Pokemon Z Land and Z Sky, Land is a sequel to X and Sky is a sequel to Y.

2. They have challenge mode. It is apparently 'so hard your balls fall off and cry tears.'

3. Southern Kalos is revealed, essentially being a whole region of it's own, though half of it is for a rather lengthy postgame. There are several brand new pokemon exclusive to the southern half of the region. The employee described one as "chain smoking Koala". There are five new gyms, but apparently they are optional as 6 or 7 of X & Y's Gyms are staying.

4. there are going to be Mega stones scattered in southern Kalos.

5. There is almost certainly going to be a big twist in the main story. the employee was pretty vague about it, but when I asked about the plot all I could get out of them was 'big secret surprise is my secret and I gotta quiet."

I can answer a few questions on more specific things, but like I said, I'm just parroting the ramblings of a drunkard, while I too, was a tad tipsy, so take these with a significant grain of salt.