I wouldn't mind being able to hook up with other players on other worlds, but I don't want to do it randomly for myself. If there is an option to form parties with players on other worlds, or do random parties (that server or another), or do server only parties, that's cool with me. More options makes it possible for people to do something that is suited for them.

But I am against only choosing one of these options. It needs to be all or none, I feel.