Instead of simply different color ghosts in the future, it would be rather awesome to have choices for ghosts with different voices and personalities. Maybe even shapes. Like the TomTom route. How funny would it be to have Snoop Dogg freaking out about a wave of hive running at us? Would make replaying missions fresh and less grindy. Can make it a reward for a new exotic bounty. Or special story events to locate a new ghost upgrade.