Here is another idea that may or may not have been thrown around. How about a player rating system? This would aleviate some problems with teaming or inviting people to SGs. Ever had someone cause a team wipe more than once in a mish even after being told what to do or not to do? Ever had a new SG member steal from the group? What is the worse thing you can do to them right now? Yell that player X sucks or robbed us and complain to support.
Wouldn't it be much better if you could rate a player and have that vote tallied against their global id so that no matter which toon they create anyone can see if they are hated or loved or just so so? Everyone would get one vote per global id, so that people can't create 50 toons just to vote a friend as a 5 out of 5 or someone they dislike a 1. If you try to vote on a new toon that you meet and it belongs to an id you already voted on the option will be greyed out.
Just in case a person is voted as a bad player doesn't mean their rating should stay forever. A method could be put into place that would require you to revote to maintain the poor rating after a set time period like 1-3 months. If you don't revote then that vote is removed. This would give a newbie a chance to prove that they may have changed. Something like a thief may need a more permanent option like a a negative rating that specifically states that they are a thief and stays for 6-12 months or more.
I think something like this could also help with the current limit on the friends list. If the rating could show if you voted on the individual then it's someone you've probably teamed with before and if they have a good rating it would be a no brainer to invite them to team or ask to join theirs.
Any one like these ideas or have a better suggestion?