This is my vision of Deviantart chat. Its a work in progress but I thought that I submit it anyway.
Most important thing what I did was the redesign. I think it fits well with the current userpage style.
User Control Panel
As much as I have been in DeviantArt chat, there has always been a problem that you don't know if your friend is there or is he/she idle. So my solution would be to have a away system. From Status you can select if you are: Online, Away or Busy. Away Message idea itself is a simple, if someone writes your name in chat window then automatic message will say why you are away. And last Auto AFK. If you set it to 10 minutes then it means that after 10 minutes (if you haven't been writting at that time) your status will go from Online to Away.
This is one of the things I will update later. Basically my idea would be to let users customise their own chat windows. This means that they can change the text colors, overall chat window background color or even change the chat skin, maybe some users like the old version more. If you have used the mirc then you know what I mean.