9. The Community
It's nicer. More mature. More civil. Players are more helpful and supportive. This is at least partially due to the removal of the specialty-based system where your party is only as strong as its weakest link. The system in GW2 is blameless, which alleviates a lot of the stress and pressure for noobs and casual players. Plus you get experience points for reviving other players on the battlefield, so it actually pays dividends to help the less fortunate.