Replace that god awful button interface with a menu counterpart, or at least an option for it.
Tabs for two different "chat" boxes, one for normal RC chat, another for npc server chat messages, thus seperating chat and npc server debugging (or whatever else people use it for).
Server flags, I would prefer a listbox editing system, rather than how it's a text control at the moment. (eg, add/remove/edit buttons)
In-level debugging feature (like F6, but limited, like an active display of level variables and the like).
Instead of having two playerlists, make it so when you are RC'd, when you open the normal playerlist you can expand and contract the playerlist (eg normal look, then to rc look with the extra property display).
I don't think the toall button is any longer needed.
All I can think of at the moment
