Yeah, that’s true. But that only means that you won’t be able to hug your mother/wife/brother/son/etc after the battle, not that you’re going to walk like a sumo wrestler during the fight. Point is, this is military-grade equipment, designed to be easy to move in. It may restrict some of the precise movements, but not the walking/running itself.
Well, it looks like a scuba helmet with all that windshield and stuff. And it protects against radiation. How can it protect being not sealed?
Your skin does not touch the ground, the exit point for the shock is to be located on your soles. If they are ceramic or rubber, then you’re fine. Mostly.
Well, ANBC suit handles this task pretty well, at the cost of 40 encumbrance. Add magic futuristic military-grade servos and voila! Moreover, you don’t have to seal every hole to get gas protection, only the helmet, if it sits tight over your neck. Considering CDDA does not have gases that damage the skin itself.