For example first,
If I want to send a message to a legion, say, "Mostly harmless" legion a message,
I would be able to search their legion page and click "send a message" button, and send a message the officers of Mostly Harmless (on a separate tab of the chat and/or archive).

The purpose for this function would be for diplomatic reasons,
for apologizing for disabling an ally, sending ultimata to enemy officers, etc.
Anyone could send messages to other legions but only officers would be able to see the message to keep the legion chat clean and simple.

for general chat for non-officers, I would second this "galaxy chat" idea
viewtopic.php?f=6&t=2975

Somebody mentioned a legion wall once. It would be nice to not have to use an artifact on someone for them to be able to respond. streamlining the ommunication too much might make ship comms pretty pointless.