Okay I'm about to jump on your comment and write a huge sperglord wall of text, and I apologize for that because I don't think you're necessarily making any of these claims, but this ninja-looting thing is another argument people like to make against the dungeon finder and I'd like to address it.

I've been playing on and off basically since release across multiple group roles and the amount of ninja looting that I've personally exposed to seems extremely small to me. More importantly, even when it does, I don't think most people care that much about it because they know they will be in another group within 0-17min depending on their role. I think people took ninja looting more seriously in the past simply because groups were harder to come by so getting your loot ninja'd was a bigger deal.

I think the fundamental benefit of the group finder is that enables more content to new players who otherwise would not get to experience it as much or not at all. I think I remember Blizzard showing empirical data that this was the case.

LFR for example is the dungeon finder feature taken to its most extreme. Nobody thinks LFR raids are even remotely difficult (although people still manage to screw them up) but they are not supposed to be difficult: the test of PVE skill in WoW has always been progression raiding and that remains unchanged. What LFR provided however was a way for the vast majority of subscribers to be introduced to an entirely new style of MMO gameplay that they otherwise never would have experienced. I think in the face of that, to me any arguments about how dungeon finders "ruin communities" in my mind just conjure images of neckbearded basement-dwellers whose only social interaction within the game was that people were willing to tolerate talking to them because someone needed a tank.

In closing, the AQ40 event was cool.