ok i know the wiki is not a reliable source but i got most my stuff from there
first off is the new biomes
RED WOOD

this biome will have moss stone bulders made of moss stone 2by2 spruce trees ferns and a new bloc called podzol will be in this biome
CLAY MOUNTAINS

will have many colors of hardend clay and dead bushes

CLIFFS

a new tecnical biome cantains dirt and stone

WORLD TYPE
in minecon 2012 they said they were going to add the skyland but did not know how well now they are going to be a world type! i am not sure if this is true cuz there is no image

CHERRY TREES
here is my source
https://twitter.com/Dinnerbone/status/361892350424911873

dinnerbone is adding a better fishing mechanics

they may add seasons

NEW FLOWERS
what looks like sunflowers

lavender
maby not but hey i could not find the name

Paeonias
there is no info as of right now jeb stated that they were used at his wedding though could this mean marriage in minecraft i hope not cuz then that stuff would be all over the servers and my head would pop lol

serveral colors of tulips

what apears to be two block tall grass

fall damage particals

ACHIEVMENT
there will be a list of ones you have gotten on every world so each world has its own achievment list

well thats all for now :)