I think if there was some matchmaking-like ability added to the lfg and lfm features, it would really allow people to jump in and pug up.
I was thinking something like, auto-search results based off lfm settings. Or lfg can have an lfm autojoin checkbox. If you meet the requirements for the lfm, it auto sends a join request. Or prompts the user if they would want to join so and so's group.