How about another direction to do things, just a suggestion here really: grappling piston-powered claws that can be mounted on vehicles?
I can imagine the best peak direction a survivor can take “power armor” is a 3x3 vehicle with heavy metal plating, tank treads, a big engine, a mounted turret, and some form of BIG, MEATY, CLAWS piston claws for grabbing vehicles, boulders, furniture, big items, etc, without having to leave the vehicle, as well as being able to slap things around if they’re close enough to you without needing to shift the whole vehicle.
Speaking of things, can a vehicle with tank treads turn while stationary? If not, they should probably be adapted to permit it.
Other vehicle improvements could be:
-Some sort of piston-powered wacky thing that is less resource intensive than a roboclaw both in controlling and building, and would “slam/crush/impact” whatever tile it’s on and all occupants of said tile for Big Damage, but does not take up space when considering vehicular collisions. Is manually activated from controls, but can be trigger activated if you apply some of your trapping skills (for stationary bases and the like).
-Diagonal movement protection: This is… a hard problem. Short of making 2 tile thick walls on your vehicle, the best thing I can figure in this case is a component when diagonal to another component of the same type, blocks movement, vision, and projectiles between the diagonal gap between the two. Actually programming it could very well be harder, though.
Granted, this is getting away from power armor and more into tank/mecha hybrids, but considering the current vehicles we can make, it seems to be ballpark capable in this sense. More readily buildable than a body-hugging power armor suit, at least.