I'm testing GW2 atm (free trial) and I have to say the towns are pretty lively there. Having something like this in ARR would be nice, even if it's just set patterns, it's still better than having mutes. NPC talking can also be used to tell more about the different races, kinda like the charr teaching history about their war with humans to their cubs.

Also, humor! Some dialogues in recent western games made me laugh multiple times, without feeling forced to do so.

One thing they should be careful about is not making the NPC trigger their speech when a player comes into vicinity, and most important, not show it on everyone's screen when someone triggers it. Imagine 800 players triggering the speech over and over again @.@;; (GW2 players will know)

@Garion: Aunt Pol was looking for you.