The problem with the current LFG system is that most people don't want to deal with others. Although it would be nice to think that it is easy to get a group by constantly spamming chat, it really isn't. I found that most of the time when I say "LFG ____", I get 1-2 people who near instantly whisper me, saying that they will join. After that, me and the party I just formed have to wait around 30 minutes until we finally give up searching for someone and decide to do the 4-man quest without our last person. While we are out tripping over ourselves and all around failing to do the content since we are undermanned, we see some idiot that is trying to solo the content by himself. We add him to our group, but he promptly rejects and puts us on ignore. That may seem like a really funny and rare scenario, but it has happened to me frequently.
The current LFG system does not make people more social. It only really causes the less social people to shy away from instances and quests because they do not want to deal with the time it takes to form a party, and talking with the party that is forming. I have gone through so many quests where NOBODY talks. It always starts off with either me or someone else saying "Hello!" and being ignored. Then it goes on to me or someone else, again, trying to make side comments in order to start conversation. Then at the end, me or someone else say "Ty for group!" to which the party responds with "K" or "Yup".
This LFG system also does not prevent ninja needing, idiots who like to rush, or all around jerks who think they are above everyone else and seek to slap people with their e-peen.
I don't really think that a new LFG tool will cause all the problems that have been described in this thread since they already exist in the game.