It would be good to emulate something that already works. DAOC splits chat messages from combat messages, which should be the absolute MINIMUM consideration for a chat interface redesign -- if Funcom can only do one thing to improve the chat system, they MUST implement this feature.
They also have implemented tabs that take you to separate panes (chat, group, guild, etc.) that exclude all other channel content except for the specific channel selected, and the local vicinity channels (i.e. say, shout, etc.).