Jet packs are more of an accessory. Full body coverage also usualy is bad for mobility. The Ground units are meant to move quick with very decent protection. The thick titanium plating and kevlar makes it nearly impossible for many bullet types to get through. Militaries today prioritize on kevlar that has proven to do a lot. With titanium being strong and light, it is perfect for mobility. And if it doesn’t do the job of dispersing the force of the bullets impact, the kevlar will do the job. You can see the armor plating all over. The exposed areas are less likely to be hit and the arms aren’t a lethal hit area.