That would be a good idea per the AFK indicator. I'd also love to see the number of people currently in my group chats...so I don't have to keep going into rooms where no one is...
I'd like to go one step further, and ask that we have the option of some kind of availability setting. Sometimes I just want to play and not chat, but I'm often too polite for my own good and end up standing in one spot for hours, IMing. I do enjoy talking with people, but lately I've felt it's at the expense of my play. I would feel so much more polite if I could set a scale of availability, from being 'here!' to 'afk/busy' to 'do not disturb'. People could still IM regardless, but they'd have fair warning as to the likelihood of a response.