Implement a system of simple gestures that can be used to signal, direct, and communicate with others without the need for verbal communication.
Purpose and Functions:
Hand signs and gestures can be used to communicate with players in line-of-sight of each other for several reasons. This would allow two primary benefits to the game:
1. Silent communication among groups (MTF Squads, researchers, Class D's, etc.). In moments where verbal communciation would betray the presence of individuals or groups, this would allow a further element of stealth while also maintaining critical communication.
2. Immersive gameplay. Following your squad leader and seeing him raise up a hand, and the whole group stops silent, listening for any movement. Creeping through hallways to see a fellow researcher waving across at you, only to see him ripped apart seconds later. Not only would these give in game moments of immersion, but RP dedicated groups could work out which signals mean what within their groups to promote tactical gameplay.
Why Do This?
Realism and immersion are the key factors here, but I believe it would also be fun. While I don't know if a full on emote system would be appropriate, I do believe that simpler gestures would be both appropriate and appreciated.
How to Do It?
The key to this I think, is implementing them in a way that doesn't break immersion but also is simple to use. Pressing a key to bring up a list of gesture types (Order, Counting, Direction, Warnings, etc.) then narrowing it down to the gesture itself could be a three-key command. For instance B-1-1 would produce the "Stop" gesture.