Going to post an actual LIKELY prediction about XY.
There's A LOT here, so I decided to "hide" it so it didn't take up the whole page.
Let's look at some facts.
There are 4 types of legendaries. Main legendaries, large-size legendaries (heatran, terrakion and such), humanoid legendaries (deoxys and such), and "cute" legendaries (or "pixie" legendaries).
Prediction Number 1
Generation VI will have a "cute" legendary
Now lets take a look at these "cute" legendaries
Five in specific (these all look similar, so I'm not counting Shaymin, and as well I will not count the lake trio as they are, as stated, a separate trio). The main one from each game.
Without manaphy, look at the types.
Prediction Number 2
Generation VI's "cute" legendary will be part psychic type
All of these pokemon end in the "-y/-i/-ee" sound.
Prediction Number 3
Generation VI's "cute" legendary will end in a "-y/-i/-ee" sound
Now take out Jirachi.
These pokemon form a type triangle.
So what comes next?
Prediction Number 4
Generation VI's "cute" legendary will be electric type
Due to that being considered a fourth starter type by some.
Next. Lets take a gander at some pseudo-legends (plus one legend), otherwise referred to by me as the "smash bros legends". Specifically:
These complete another type triangle
Two have appeared in smash bros
Prediction Number 5
Zoroark will be in the next Smash Bros
I know this isn't XY, but it relates to my next point
Leading in to my next point
Prediction Number 6
We will have a "smash bros legendary" in gen 6
But what about it's type? Well, one more type can go with that trio.
Prediction Number 7
Generation VI's "smash bros legendary" will be ghost type
Legendary is not literal here, obviously. But something of similar shape and stature. And if not ghost, then:
Prediction Number 7.5
If not ghost-type, generation VI's "smash bros legendary" will be flying type