While I dont agree with the dying thing, I do agree something big is missing. Since the merge I regularly group with players who are completely unfamiliar with game. Just a matter of making a bigger percentage of them stick with it.
The merge will be a play a huge part. With a greater number of quests than at launch to keep new players busy, there are now a sufficient number of people to get groups.

I do also think it is the role-playing/just hang out in the world(Stormreach) living their characters life type of players that are most noticably absent. I think they already figured this out though, they are adding many of the side things that will flesh out who a character is. Questing alone is not enough for a very large number of people imo, they need more. I think "the more" is coming, albeit a bit slowly.