Hello,
My observation is that when there are few AVs around, bubble chat is best because then you can visually focus on the AVs and see what they say etc... and if the chat is gesture enhanced then bubbles is the way to go.
However, when there are a crowd of AVs, then the usability of bubbles break down dramatically. There is a loss of ordering in conversational statements and it becomes difficult to identify who said what last (even though some form of visual highlighting is used to grab attention).
Would it not be neat therefore to set a threshold in Preferences... ie a number of AVs say N, so that if number of AVs in proximity < N then to enable Bubbles automatically and when number of AVs in promity >= N then to switch back to traditional chat display...ie with the conversations following each other down the screen?