apart from a few bugs power armor works as intended. I mistakenly asked a few of these same questions as well, and it was explained to me a bit like this:
‘POWER’ armor is a large suit of thick metal plates and actuators for movement. un-‘POWERED’ it’s very difficult to move. plug that bad boy in and you are a walking terror device.
A hauling frame (think backpack rig) allows for space to be added.
the UPS doesn’t last long. this is also intended. these are 0 generation suits, produced at the end of the cataclysm with no further development (that we know of now). These suits were deployed a few yards ahead of a line of supply personnel to help with the suit.
these ARE NOT Fallout 3 power suits. think Iron Man MK I without the jets and mounted weapons.
Glasses I suppose are fixed in .5, paitence friends, and until then store the suit in the trunk and drag it out when you park in the middle of town and break face there. don’t walk to the battlefield, just drive and get out 
and on the plate armor thing, I’ve seen guys in well made full plate do cartwheels. this was because it was made FOR them. the stuff we find in the game most likely wasn’t tailored for our player and therefore is fairly restrictive. just sayin.