I realize it's VERY early to mention this, but I've seen people leave games because the chat was too strictly (and some would have argued unfairly) moderated and also others leave games where chat was unmoderated or loosely moderated and it got just nasty and vile.
Tribe chat should be private and unmoderated (with the possible exception of real life threats). If players don't like what is there, talk to tribe officers with a view to getting it calmed or else leave the tribe.
General chat is more tricky. My personal preference is for a moderated sensible channel AND an unmoderated "chat" channel, with the ability to turn off certain channels.
Officer chat for ranks above ???? within a tribe. Not moderated obviously.