I was a big fan of Guild Wars, and really liked the "Jump in and get to it" way the game worked. I started all the way back on the World Preview Event, which I played just because it was free and I had a few hours on a Sunday following a trip; I stayed on until the server shut down and was thoroughly addicted. I did the beta weekends after that, and since the game has launched I bought the collector's edition for each game and have logged over 5,000 hours (admittedly, some of that was playing the AFK rings, also known as nine rings).
I'm excited about GW2 if only because "It's more Guild Wars!". I'm concerned because the game seems to be departing from the original on so many other points that I worry it won't keep the solid gameplay elements I liked from the original. I don't like "all the new races", not because I don't like new races but because there's so many new ones and so few of the old ones. The only old race is the Charr, and although I don't want to play with it myself (ignoring gameplay mechanics at this time) I'm glad to see it as an option and look forward to playing with people who play them.
I don't like the Asura much. I really dislike the Norn. I'm charmed by the Sylvari, and because of the original game I'm partial to humans. Most of the races had some representatives in Eye of the North, so you know who and what they are. The Asura are ass holes, the Norn are vikings and idiots, and the Charr are sheep who will listen to whatever their leaders tell them (seriously). The reason these races were included in GWEN was so players would be familiar with them.
However, what happened to all the cool races that were in the first few games? Why can't I play a centaur? I could feel their bitter, angry vibe well. Or be a Forgotten, a sort of snake person with arms, who figured prominently in the desert and acted as guardians in various places. Why can't I be a Tengu, who even had a henchmen (Talon Silverwing) in Factions? The Tengu were stoic and honorable, while the humans they were opposed to had a tendency to be greedy. These are missed opportunities that I hope will be available in expansions, if not at the start. I'm particularly interested in the Forgotten, since in Nightfall their primary job ceased to exist. What have they been doing since then? Did their race find another torch to pick up?
Mechanically, I worry that the game will stray too far from the original game's fun. I like being able to go back and redo anything; I was pleased with Nightfall's branching and semi-individualized story line mainly because you could go back and play the parts you missed due to choices you made. I'm concerned that GW2 won't really have that option for us.
I'm also unhappy with the weapon/skill design. I wouldn't mind weapons that come with a set of skills if we could then customize them a bit. Ripping skills out and putting them back in would be fun.