(the following cut and pasted from AION forums)
-Changing Seasons
-Gfx Engine update. New Dynamic Lighting system implemented
Mounts:
-Single Player Mounts
-Passenger Seat on Some Mounts
-Combat Mounts
Player Housing:
-Decorate them how you want.
-Personal Housing.
-No Mention of Guild Housing.
-Tons of crap can be decorated, furniture and outside
New Skills
Possibly New Classes (Prolly a Third Class Change)
New Weapons:
-Whips
-Crossbows
-Shields That Turn into Grappling Type Hooks
Massive Ground Sieges with massive Siege weapons.
Swimming Finally.
Underwater Quest Hubs.
