it is an interesting suggestion, but I am thinking about how it would be practically implemented....
You have to navigate to the contact list, and select the player to send the message too, and then choose to send voice message, hold the button while recording, all of this sounds reasonably until we start thinking how would this be done with a controller, and being able to fly at the same time.
I have this issue with the chat message today, that it prevents you from flying while chatting.