It would be pretty cool if 343 were able to incorporate your XP Rank Level Live on your Armour as you rank up to be seen in game. (Predicated on there being a H3 or Reach style Emblem for XP) Maybe the Higher you get to ‘max level’ the emblem glows or changes in unique ways?
That would be cool.
They could possibly do rank on one shoulder, emblem on the other, and then maybe like your 3 or 4 letter/number service tag on your chest like Chief has his 117.