However, my main concern is that while games have found numerous ways of helping good people ignore, avoid, or punish bad behavior, there seems to be little if anything in place to help good people find other good people.

Doesn't the guild system built into most MMO's do this already? Many guilds have websites and/or forums with their 'manifesto' and type membership they are looking for.

Maybe separate servers are the way to go so you could have a 21 year old + server, hardcore and non-hardcore servers and maybe an obnoxious dickheads server! Thereby people could find similar people to play alongside