I would like to suggest this to the team since some find this a convenient communication method during dungeons/trials/raids and especially when you have your hands busy. and it's hella fun.
Some ways to implement this~
-The sound can be heard as 3D (volume changes based on how far away or close the character is from the recipient)
-It should be optional and can be changed in the duty finder/party finder settings
-Now to distinguish which voice belongs to which character, a volume meter should be placed next to the character name on the party list.

Some downsides to this is people going on duties just to use voice chat.

What are your thoughts on this?