A checklist of which chats you can toggle on and off (General chat, Party, Alliance, Whisper, Group). Also, if you block a Symbol Art, that Symbol Art should be treated as if you have the current Symbol Art option turned off to eliminate the clutter of empty white chat bubbles on a person's screen. If it doesn't already, have blocked Symbol Arts unable to be in one's History list.
A toggle feature to turn stamps on and off, with the same options as the first suggestion to filter spam.
A toggle to turn cut-ins on and off.
Converse with fellow players