RUMORSthat Pokebeach has posted but has not yet confirmed. They believe the source is legit, but they don't want to jump the gun in case they're false:
Fairy will be a new type. It is weak to Poison and Steel, immune to Dragon, super effective against Dragon, Dark, and Fighting, and Fire and Psychic-type Pokemon take half damage from it.
Sylveon is Fairy-type. Some older Pokemon will be reclassified to Fairy, such as Mawile (Steel/Fairy).
Mewtwo has two new formes, not just one. Both are activated via items.
The professor's English name is Patrice.
The Starter final evolutions are Fire/Psychic, Grass/Dark, and Water/Fighting.
The first Gym is Bug, the second is Fairy, and the fourth is Fighting.
A few attacks will be dual-typed.
There will be a new type of battling style that Flying-type Pokemon and Pokemon with Levitate can participate in.
You will be able to see a Pokemon's EVs at a certain in-game facility. You will be able to boost the EVs through mini-games. It will take about two hours to get one stat to max EVs.
Out of all of these, the most plausible rumor, and the one I'm the most excited for, is the new Fairy type. I mean, just look at the designs of Sylveon, Xerneas, and Yveltal. They don't look like they belong with any of the current 17 types already in existence. They have a mystical, almost otherworldly look to them, which is what Fairies in folklore and legends are all about. Not to mention that I love anything that has to do with magic, which Fairies most certainly are. Also, Dragons and Fairies don't typically get along, which explains the type advantages. I was kind of hoping for Light type instead, but this one works better as it can be a duel type for Dark and Ghost while Light cannot.
Also, here's how I see the type match-ups for it: Fairies were mythical creatures that died out due to diseases (Poison) and because man overtook their habitats (Steel). They are magical beings that can lift curses (against Dark), like to play pranks on humans (against Fighting), and again, are mythical creatures, so they have defenses against other mythical creatures (against Dragon/immune to Dragon). I'm not sure about the 1/2 against Fire, but Psychics posses a bit of magic themselves, being able to fend the Fairies off.
What are your thoughts on the Fairy type and these other rumors as well?