This one is more for discussion than an actual idea, actually.
Here's to hoping for a Free-For-All mode in release. No teams. Last man or woman standing wins. Pure and simple.
Everybody could start at one central point and fan out in a matter of a time limit before shooting can start, or everybody could start at their own position. Either way, I'd love to see how this plays out.
Would you shoot others on sight? Or would you team with them? ...Or would you team and turn on them later?