In my personal opinion, I think it would be pretty important to add scrolling UI, more than 8 lines back could could include important information you didn't get a chance to read, and you might not want to wait to go back to the lobby to read it. Perhaps the reason it sounds low-priority is because we normally play the sessions with Mumble, so now we've played some 1v1s, the chat becomes more important? Perhaps the full chat should only show when you start to type, to avoid clutter, and then when you're not typing you can't scroll?
Also, while we're on the topic of chat suggestions, perhaps the names could be the colour of your Lix's colour as well? Sometimes I found it hard to differentiate between which messages were mine and yours.