I put more hours into GW1 (+1,200 hours) than any PC game except Counterstrike and Team Fortress 2. I completed most of the adventure mode at least once, but arena PvP was my primary love. I had a blast tinkering with new builds and testing them out on the battlefield with all of the great tools the game (and expansions) allowed.
With that said, I've been trying hard to fall in love with GW2, but I just can't. I feel they dumbed down the skill system by forcing skill packs on you instead of allowing each slot to be chosen by the player. Plus they got rid of the primary/secondary dual class system, which really opened up a wealth of build possibilities. The fun of creation isn't the same from what I can tell.
Also, my favorite class the Mesmer was revamped in ways I don't care for. A lot of the pressure skills, like Hexes, stances, interrupts and energy drains are gone as mechanics in this game. You have clones to play with now, but that seems somewhat like something the Ritualist (not in GW2) would use. There is a MUCH greater emphasis on melee fighting as a Mesmer, which rubs me the wrong way. Plus I remember being wow'd by the graphics in GW1 when it first came out, and the game itself was beautiful for its time. GW2 visuals seem merely decent, which is unfortunate. I dunno.
I do appreciate some of the mechanic changes, especially those that I was begging for in forum debates long ago. For instance, I hated that the Monk in GW1 was the only required class for most team builds, especially in the arenas. A team with a primary healer on it had a very high chance of winning vs. a team without. In GW2, there is no dedicated healer, and there a re a ton of self heals/defensive buffs for all classes instead.
I also like the fact that players don't need to carry a rez skill, allowing for the skill bar to be open for more cool options. The weapon mod system and the ability to switch between multiple builds on the fly looks great, and I like the dynamic quest system for adventure mode more than GW1s Fed Express game play. Another improvement worth mentioning is how skills between team mates of different classes naturally interact with each other in real time to create some amazing combos.
I want to like the game, but have a hard time generating a strong interest. Maybe I'll warm up to it if the reception is generally strong by players.