The only really remarkable changes I've noticed taken place this year would be the mail system (ability to interact with people when they are offline; has a 5 unit limit) and chaos tower (tower where you climb up and defeat monsters and bosses, giving you amazing exp and a chance to gain altiverse, weapons and armor in different level tiers that have a chance at being better than boss sets).
Edit: Ah, they also added new third job skills. They're worth checking out depending on which job you are.
I would say come back to Trickster, it's still pretty nice, but GameGuard has been been added to the game |: You might not even be able to run the game, lol.
I would really just wait until that goes away.