I miss half a day of reading this thread, and yall machine gun out the replies, so this topic might be two or three pages back, but I wanted to chime in on it lol.
As for a LFD feature being good or bad for a game, first off, I feel that the design of the game itself is the greatest factor in whether it is a good fit or not.
For example, with a game like EverQuest, a LFD tool is just not a good fit overall. The game is designed around the concept of a virtual world you interact in, and the dungeons fall perfect in to that design (at least up through the first five or so expansions). These are large complex dungeons (for the most part) with rare spawn camps (even though SoE never acknowledged camps 0.o), and you are expected to spend many hours in the same group at the same camp playing together. You would never want to do that with a group thrown together via a LFD tool.
In a game like FFXIV, a LFD tool fits in perfectly because all of the dungeons are small linear dungeons with a hand full of boss mobs you battle along the path to the last boss mob. It's a run and gun dungeon design with the intent of only taking 10 to 20 minutes per run. Therefore, the people you get stuck with from a LFD tool doesn't matter too much.
With World of Warcraft, its a little more tricky. Yes the dungeons are linear for the most part, there are no camps so to speak, and you follow the path from boss mob to boss mob until you reach the main boss mob. So, it fits the criteria for a LFD-enabled MMORPG. But... some of the dungeons in the early part of the game weren't really that short. Also, it's supposed to be a living breathing virtual world very much like EverQuest. In fact, it's even more so a virtual world than EverQuest because there are no zone lines (or at least very, very few).
It's almost as if WoW is a hybrid between a virtual world MMORPG and a lobby MMORPG.
There are definite benefits to having LFD, and there are definite benefits for not have LFD. I don't think you will ever get everyone to agree on one way over the other. The question is will Blizzard decide to flip the switch back to a more virtual world MMO after seeing the success of Classic, or not.
I personally think they won't simply based on the fact that they didn't even want to do a Classic server in the first place. I kind of feel like this Classic experience is being created as a one off to say, "here you got your classic, now shut up and buy our next expansion for current WoW". I think that there will need to be major, major success to make a change.