Currently, when you’re on Feed with all channels ON and press Enter/Esc to open chat, you will be set to speak to Global Chat. That makes people speaking on Global even when talking with their group inside dungeons or other content in group (I know there is /p and /a area).
However to unclutter the Global chat, I think it’d be more efficient to have a /s /say (and this would be the automatic chat whenever you press Enter/Esc to open chat. This chat would only show the messages for people around them, within their sight and it would create a chat balloon over their heads.
People would have to intentionally go for /global when needed.
A trading channel would be appreciated as well, but the above one is way more important IMO.