Araiia
o.o hm, what has changed about the game? It's been over a year since I looked at GW2.
There's been a couple major feature packs that I can remember over the past year or so. One implemented the wardrobe system for armor so you don't have buy new sets every time you want to transmute something. This also allowed dyes to be accountbound rather than soulbound so you wouldn't have buy each color on each and every character. Minis are also part of the wardrobe system now.
They also revamped the traits system so you have to complete certain tasks to get certain points (if you didn't have them already). This gives you a bit more to do throughout the game and adds to the endgame.
There are a couple of world events that I'm pretty sure weren't there a year ago that are fun -- Tequatl, Triple Trouble, etc.
The biggest change though I think is the megaserver. Maps are a lot more populated now and it's way easier to do map completion/JPs because there's a lot more people around. Some people hate the megaservers but I think that they're overall pretty great.