It dosen't have to be called GIMP it could be GMP *Graal Messanger Program* or PIMP *Personal Instant Messaging Program* i like the name PIMP more
Auctualy being able to join only one server instead of having the players from all servers on your list is better. If you wanted to you can run the program more than once to log onto other servers to participate in conversation on there as well.
Have toalls in the prog too. Also, about people excessivly swearing, since this prog would be like an RC *meaning you wouldn't be in a level* there wouldn't be a way to "jail" people when they swear execssivly or are harassing people. To fix that problem, when someone would log into the prog it would check the server to see if that account is in jail/banned. If that account is jailed/banned then it would disconnect you and a popup message would appear saying "Cannot log in, account is jailed."
As for being able to access the p2p servers, i think that it should be allowed since all that person can do is converse with other players. As for the head that would show up when you log on. i think it should be a head specificly for the prog users. That way you can tell or not if that person is on.
There should also be an option for the auctual players to ignore messages from the prog users.