New Features (currently announced):
1.There will be firearms used on certain characters that enables them to use black powder to shoot. There is said that there is a twist on the firearms option just as there was on shadow walk for assassins in the original. There will be recharge and reperations for using the certain skill or weapon.Since Guild Wars Gold 2 takes place 250 years after the original Guild Wars these weapons and more have been added.
2.You will be able to swim/walk under water! With this comes Dungeons under the aquatic floors where you can work together or alone and farm gold. This feature has had many bugs and some say is the reason for Guild Wars 2 delaying its release. This however will open up Guild Wars Gold 2 expanding its possibilties.
3.Maps will now be much larger then normal and have surprises and bonus missions added to them. The maps are supposed to be interactable and change the way you finish or play the rest of your mission. Certain routes you take and the way you travel can now also affect your mission and gameplay.
4.Ive saved the best for last. There will be something called "World PvP". The levels will be on a large scale and take a bit of time to complete(Somewhat like the raids or instances). You can team up and take control of guard towers or take over a castle. This in time will help your world as a whole and increase drop rates and help with energy regeneration.