I know this was posted before, but advanced squad commands would be nice to see. Ability to set crossfire sectors or determine the last man on the door. I was with the Army Infantry, so there may a good deal of difference of training from the Marines. As well, I served beginning six years after Fallujah began.
Cross fire sectors are not always viable, but they can be effective. Even if it’s one other to help push back enemies. Cover bounding commands would work well in a system similar to this, but that would be more associated with a push command.
Being able to determine who the last man is on a door would be interesting to see, even if it was always the player. They were the ones to kick open the door and try to supply the first person cover as they entered. Usually this was the one who held the SAW.
A wall mounting system would be interesting to see in play as well. Again, not always viable but it was a tactic put in place to provide cover and weapon stability. Rounds could still penetrate, but had a possibility of being stopped or slowed down.