I had an interesting idea when I was playing Halo 2 for the first time in a long time. When the Arbiter was stripped of his rank, branded as a failure and given the armor of the Arbiter the prophets are talking about the past Arbiter's before him. As they are talking about them the camera angle changes and shows the crypts/tombs of the previous Arbiter's. So that got me thinking... What if 343 made a Halo game that allowed you to play as past Sangheili warriors who also failed in their duties to the prophets, who eventually became the Arbiter's? That would be fun.