I think a cool feature would be...well this would only work with steam users...but to have chat only be via steam chat...not ingame...so when you hit enter you start a chatroom just for that server and everyone joins and you talk that way...
This would prevent people talking so much that the text scrolls up over all the gameplay in the middle of the screen...which I find very annoying...
The problem there is that not everyone plays this via Steam (myself included). And I think hitting Enter to open a chatroom via steam (which would have to be accessed via Ctrl+enter to see the Steam overlay) could be problematic.
Another possible solution to the chat window thing could be in the way WoW handles it. A small, but wide window in the corner of the screen, with three tabs: 1 for chat and game info, 1 for just chat, and one for just game info.
(example of how WoW does it). Clearly it doesn't have to be this elaborate, but I think there should be some way to customize the kind of information that's being spat out of the game -- a way to distinguish between chat and game info.
This is by no means an endorsement of WoW, which I happen to think is a pretty soulless game. But that's beside the point.