I love the idea of having multiple windows to type in, would it be possible to add a list of people connected to that window? IE you could a chat group with 5 people in it, there names would be on one side and there would be a title on the top. The main reason I think this would be useful is for factions, if the faction window showed who was on it would be a major step forward. Plus you could add functionality like being able to click on that persons name and add them to your friends list or send them a tell.
Just some more ideas, are any of these ideas going into the client any time soon?