God, I hate the new power armor.
My every build now has to be around damage reduction without it.
They made power armor a generic frame that's identical with cosmetic outer plates.
I wouldn't mind it so much if each frame were a specific model and actually different.
Older T-45 suits/frames running off of the batteries works, they're early model suits and lack the refinement of later models, losing power should just lock the player to super slow strength check based movement speed until the player exits, and it should be painfully slow, but also be the easiest to salvage as far as skill checks go.
T-51b is the pinnacle of pre-appoc tech, and as the infocard clearly states it has its own micro reactor, power shouldn't be an issue for a fully repaired suit, ones found in the wild should start to be having the issue of the reactors fuel having degraded and lowered power regeneration, but that should only mean power regenerates slower, it should still have infinite power, and this gives science skill something to do at high levels: refurbish and refuel the suits power plant, or remove the reactor unit and replace with a T45 battery unit as an interim solution when you have the repair skill but not the science skill to refuel it.
Enclave advanced power armor is much newer and in most cases should still have a full power reactor.
Brotherhood T-65 should be treated as a BOS post war mod of old T45 suits, heavier armor, but still uses the battery in most cases.
As for the gameplay, the plates are basically like armor in Oblivion, you take enough damage and your armor just falls off leaving you 'naked'.
That's dumb, especially when it's a swarm of low leveled critters or something with low damage.
DT/DR as done in new Vegas handled it right, if the attack is too low leveled it shouldn't even scratch the power armor, so rats and weaker critters just have no effect upon the armor, and just walking should inflict damage on them if stepped on.
Do something similar with weaker guns and mele weapons, just have no effect unless it's a critical hit at the eyes or reactor module, and even then have those parts have their own health value that you can repair if the requesite skills are high enough or you find a vendor capable of it.
Now, for suit mods, funny and reasonable stuff needs to be added.
Using a minigun or belt fed ?
You should be able to mount a drum/container for the ammo, provided you craft/find/but one, that lets the weapons ammo capacity grow significantly.
Also, stop with the full auto does less damage mechanic, gun balance in further games should be based around the bullet, with the barrel length affecting range/accuracy and projectile speed and having a modifier to apply to the rounds base damage, shorter barrels doing lower damage, but barrels over a certain length having both sway and momentum affected by the players strength and agility (mitigated or removed by power armor).
Each gun, both its weight and ammo type, has different sway/momentum values, higher momentum mostly meaning longer barreled weapons cannot be snap aimed as easily and the aim will bounce around a little, with sway being how steady you can keep a weapon when aimed at a target, strength and agility should be the main factors for this, with weapon skills also having a lesser effect since a skilled shooter would do better with a too heavy gun than an unskilled shooter.
Edge cases would be things like shotguns or mini guns, since shotguns are spread based unless using slugs, and miniguns have additional sway and momentum issues due to the barrels rotation.
All of that would also give gun mods more of a purpose, a bipod let's a sneaking player stabilize a longer barreled rifle, a compensator reduces how much recoil throws the guns aim around on screen, etc.
I mean it's a RPG not a MilSim, but that doesn't mean RPG mechanics can't be used to express realism, and holding that standard would actually make balance easier too.
Now, energy weapons, I'd say have that stuff be greatly simplified, weapon weight/length barrel sway remains in effect, but otherwise they should have no real recoil or such, at most a jerk at lower skill levels due to trigger pull that any gun skill over a certain level mitigated and removes.