It's also terrible for multiplayer, if other players can't jump in/take over conversations. I don't want to be an observer in someone else's game, and I don't want to have to be constantly considering whether I need to hang back to avoid getting in certain conversations or rushing forward to make sure I'm the lead for others.
Combined with the (at least earlier patch??) detail that you had to manually click on allies' conversations and thus would often miss the first line of dialogue...ugh.
