I think setting up a custom chat channel system like may other MMORPGs have would be really fun, convenient, and solve some problems guild representation makes for groups of friends. If you want to chat with a group of people in your PvP guild, but represent your PvE guild while doing so, currently you’re left out in the cold. Custom chat channels would change that.
They’d also help streamline mapchat – instead of having to sift through other people’s convos to get your updates on events, someone could make a custom channel to either get only event updates or to contain the miscellaneous chatter. They work great on other MMOs, no reason to think they wouldn’t work here.
It seems like a relatively easy thing to implement, with big benefits.