In Halo Reach, no one ever communicates with their team, therefore a full party team will demolish a team of randoms easily (most of the time)
So I propose something to encourage teamwork and help coordinate the entire team without even having to talk. it would be extremely similar to spotting in Bad Company 2 or in Crysis 2; you would push up on the D-pad and enemies would be sighted (be highlighted or have an arrow above enemy) it would work with enemies, vehicles and objectives, even being able to highlight power-ups (if there are any) and power weapons. It would also be able to spot if an enemy has a power weapon, i.e sniper rocket or anti vehicle.
This way, teams can coordinate attacks, warn of incoming dangers and actually have a decent chance if no one on their team is communicating.
So would you want this in Halo 4?
This is pretty cool in BF2, but with Halo being on much smaller maps I think it kind of ruins strategy. It’d just be a bailout. In Halo, people SHOULD communicate. People who communicate should have the upper hand over those who do not. It’s not very hard to talk to each other.