My idea is that people with a 2nd display get the GPS, the watch or even the map on the 2nd screen. Everything that has to do with tactics could be displayed there and on the main screen you get the "normal" game.

This would also be great with vehicles. For example: if you're inside the Hunter GMG as gunner you have a HUD display. This HUD display could be shown on the 2nd display while you still see yourself sitting in the vehicle on the 1st screen.