I would love the ability to chat with my active neighbors, but this might be difficult if each person's chat box is based on who you've discovered.
Say Player A discovered Player B, but Player B has also discovered Player C. So Player B can chat with both, but Player A and C won't see each other. It could make for some awkward conversations when the other half is missing. Multiply that by how many players who might be in the chat box and it could get annoying.
Another option would be a global chat box, which you could opt out of, but that might be too many players. The ideal solution would be a single chat box with channels you can join or leave at any time. Possible options could be "Fellowship," "Trade Partners," "Discovered," "Help/Advice" and various guest race channels. Each channel should also have it's own color font to distinguish between them.