Want to see an amusing "leak".
Gogoat is standalone, but there are "two" of it. The Gogoat CoroCoro revealed is the male Gogoat, there's a female Gogoat (with separate art, and stats/moves) which is much smaller without horns and can't be ridden. That's the one you can see in the background in the trailer.
You're given Gogoat as a gift around Miare by one of the Rival character to demonstrate the Riding Feature. Riding is limited to a couple of areas, but there's a pretty in-depth racing mini-game as I've mentioned which is the new "Contests".
Mawile receives an evolution, in which it has two little mouths instead of one, resembling ponytails. I think it's meant to be a reference to Hatsune Miku, because the resemblance is pretty strong when it comes to the hair-style. I don't know how useful it is though, but it can learn Quiver Dance.
Xerneas represents the "purity of the earth", is Fairy. In Kalos Lore, Xerneas rebuilt the region after war devastated it.
Yveltal represents the "ambition of the sky", and is Dark/Flying. In Kalos Lore, Yveltal appeared during wars and ravaged both sides and the entire region.
Xerneas and Yveltal represent life and death, and the cycle of it. The Kalos Region has had countless wars, in which Yveltal destroyed the region and Xerneas rebuilt it, although, since the advent of Pokemon Battles and them being used to settle disputes, Kalos has seen a prolonged peace for the last couple of hundred years.
Team Acid and Team Base.
Acid are the more "traditional" team, punk-rocker/bikers who steal Pokemon and experiment on them. Goal is to create the "Ultimate Type". Leader is a girl with long, long, long hair that she sits on, Admins are themed after venomous creatures. One dude has spider-leg dreadlocks.
Team Base less evil, more misguided. They wear those Tai Chi suits, with the button flaps forming a B, and want to obtain power to protect what they care about. They steal Pokemon from trainers they deem weak and raise the Pokemon themselves. Leader is an old man with long, flowing white hair, yet very muscular. Rather than Admins, subordinates are four sages based on the Saint Beasts.
Neither are "version based" like Aqua and Magma, they appear in both versions, although when and where you fight them is slightly different.
This guy is most likely trollin.
. Why you had to nerf Dragon Game Freak? *shakes fist* 
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