I was wondering why this is not in the game yet, and hope it will some day:
Rescue a hostage and lead it to the chopper. Here are different variants possible. Maybe Fireteam first needs to find them, and then bring him or her to the chopper. This way the predator could try to find the hostage first and wait for the fireteam with traps and so on. Of course there needs to be special commands to make the hostage follow you etc. And it would need several specials: Either the Hostage needs to be non killable. OR if it gets killed by the predator it leads to loosing a ton of points. Another option would be that a player would play the hostage (one random from the fireteam).
Variant here: If you play the hostage you can heal others but can not use weapons.
Oh i really would like a mode like that.