I'd like to see achievements related to working as a team rather than just one-man-army type stuff.

Examples:
  • Second coming: Res 10 people with a single revive grenade.
  • Energizer: heal/repair a single target for 5x his health pool
  • Armory: have a single ammo pack accessed 50 times
  • Second fiddle: get 10 assists in a row.
  • Finish Him: Kill an enemy by dealing less than 5% of his health in damage