7. The Leveling System
Here's some icing for the cake. Going from level 75 to 76 in GW2 takes the same amount of time and experience points as going from level 9 to 10 (approximately 90 minutes, according to the experts). Leveling from 75 to 76 in WOW can take years. Well, maybe that's a slight exaggeration but not much. Another wonderful aspect of GW2 is that you can go back to areas of the world you missed and quest to your heart's content. Even if the area is designated for lower levels, GW2 nerfs your character to the level of the region your playing in despite your character's actual level. So no matter what quest your character is doing, you will still get the same amount of experience points you would have had you completed the quest at the appropriate level. Further sweetening the deal is the fact that drops are based on your actual level, so you will always be able to score good loot, even if you're playing in an area designed for much lower levels. It's a fresh take on leveling and it keeps every region of the entire map pertinent at all times.
8. Multiplayer
Gone from GW2 are the parties of 5 and more that necessitate Healers, Tanks and other specialty roles. In the traditional 'battlegrounds'-style PVP, players are all boosted to level 80 with their skills maxed to balance the playing field. In the server-spanning World versus World mode, large scale combat takes place in a persistent world (separate from PvE) that enables players able to join in or quit at their discretion, all the while gaining experience points and rewards that directly transfer to their PvE character. No fuss, no muss, no waiting in cues for tanks or healers.