without getting hyped or following it too closely i am looking forward to this game for the following reasons:
world pvp without factions
80 levels but no exp/time per level curve.
i really disliked the little time i spent with gw1. but gw2 seems to address the issues i had with it.
They're also revamping the skill system. You get 10 skill slots now, 5 are weapon and profession dependent, which can be changed by changing weapons, and 5 which are profession and race dependent, which can only be changed out of combat. One slot is reserved for a healing skill, and one is reserved for an elite skill.
On top of that, they are also attempting to lower the possibility of bad skill combinations, such as bringing Gash (which requires the opponent to be bleeding) without bringing a skill that causes bleeding.
GW was pretty unique in the way its skill system worked, limiting the skills you can use at any one time, which forced you to pay attention to what skills you had (unlike WoW which allowed you access to almost all of your skills at any time) to be effective. GW2 will be a little more open, with 2 more slots (one dedicated to healing and another dedicated to an elite), but it seems like it will still have limitations so you cannot simply use whatever skills you want whenever you want like most other MMOs.
In short, Tactics is still important in GW2, unlike virtually any other MMO out there (that is, you actually have to plan your skills and what not out beforehand, instead of just changing on the fly whenever you want) but it doesn't seem quite as limited as it was in the original, which can be a good change.