I feel like the way conversations is currently implemented in co-op is a missed opportunity.
As far as I can tell, the only "influence" other players that are listening into a conversation currently have, is to suggest dialogue options to the active player by clicking them, after which the active player will see a list of what conversation options were selected by which player.
It is however still entirely up to the active player to choose which option to pick as well as his or her character being the only one who is active in the conversation.
What if instead of just suggesting options, the other party members can actually participate in the conversations?
The way something like that could work would be for every player to be able to select a dialogue option and then roll a dice, whoever rolls highest will be the character that talks and will use whatever option he or she chose.
This would make for a lot more fun in multiplayer and make sure everyone feels included and engaged in the story and would also just make for a lot more interesting storytelling instead of just having a bunch of static voiceless party members standing around in the background like statues smile