Indeed, the focus of each dialogue should turn to all players in multiplayer, like in the Baldur's Gate series, so the other player won't feel left out. The left-out player quickly looses patient and gets distracted by anything else, like the many NPC shouts/spams of areas.
That doesn't really help to dive into the story and quests, especially if you are only given a boring moving text-screen and a little in-game book to read as introduction what the heck this adventure of so-called "source hunters" is all about.
It would already help a bit if the overhead-texts of the watched dialogues would be displayed about two seconds longer to follow them over the NPCs instead in the spammed message window.
I would still prefer a forced dialogue for all players with greyed-out dialogue options for the non-initiating dialogue-player until a two-player choice in the end is required.
