The quick version, ArenaNet nailed it.
After 10 years of MMO games I've become highly critical of all the recent games that have attempted to break into the market after the success of WoW. Boring, dreary, repetitive and generally full of bugs they all fail hard in some way.
Guild Wars 2 is non of that. A breath of fresh air in an otherwise stale market. Gone is the instanced world of Guild Wars 1. Gone is the trinity of tank, healer, dps. Gone is the concept of quests! At first this is all confusing but as you start playing through zones the freedom to do what you want and not just follow a series of quests makes so much sense. Just grinding out creature kills won't get you levels, actively playing the game and joining events will do far more for your playing experience.
Most of the faults with the game are minor and are already being fixed by the developers very quickly. The only complaint that I have is sometimes events can be come repetitive, e.g the 3rd time you fend off a harpy attack does dull the entertainment value of it. But you can always move to a new part of the zone and get involved in other things.
In other games you feel the urge to rush to the level cap to start playing the game. But here, you are playing from level 2 onwards. So there is no urgency, no rush. Just sit back and enjoy the ride.