Your suggestions for chat settings are spot on and I am wildly surprised Bungie has not added this. There are two polls I know of concerning Proximity chat, this one and flipassassin21's http://www.bungie.net/7_Proximity-Chat/en/Forum/Post?id=65449285. Both show a large margin of players want this implemented. DayZ has demonstrated how it can be a boon to immersion and in some cases, a burden.