I think it would add a lot if you could look around freely during play, no matter who's turn, to allow players to see their health and items. However, most importantly have the head look where the mouse of the user is, or look at any point of interest it hovers over. This would enhance gameplay by showing other players whether its their turn or not where players are looking.
It would also allow players to communicate mid game by nodding, shaking their head, nod to the beat, or stare at another player.
Having the players stare off into blank space as they make decisions feels a bit lifeless.
Animation improvements. The animations for actions are fine but also feel somewhat lifeless. There is no shake when shooting yourself. I feel like actions like using items could be a little more interesting and add more character to the players. For example; players cover the phone so nobody hears, hand shakes when using adrenaline.
I want to bring back the charming animations from the campaign but keep them quick.
A** radio** or some way for players to choose what song plays in the background. I love all the music in Buckshot but I don't want to be restricted to just the multiplayer tracks (as good as they are!). Plus, once again this can add something to do when it isn't your turn.