Okay, so some shady "reviewer" has apparently gotten X and Y and is leaking a bunch of info. Some of these look pretty legitimate, but as usual take these rumors with a giant grain of salt. I'll post the main points in bullets and the sources below.
- Froakie's final form is called Greninja. Here's what it looks like.
- EXP Share is obtainable early on and can now share XP with your entire party.
- Only 70 new Pokedex entries, the lowest amount of the six generations.
It looks legit to me. I kinda predicted there wouldn't be as many new Pokedex entries this time around, but 70 is a lot lower than what I was expecting. Maybe they consider the Mega Evolved Pokemon to make up for the difference?
Update: Forgot to mention that Chespin's final evolution is also there, but only the back of it.