I didnt read through the topic, so forgive me if i reapeat someone.
IMO PA should not be usable by anyone. Imagine big gunners, or even small gunners with those, thats just OP. If you give PA to DPS fighters(BG, EW, SG) that would make them a well rounded fighter dealing high damage, AND have surivability. Instead of making PA extremely rare by limiting the total quantity, limit the users that can wear them.
My idea of implementing PA is to have a fighter that cant do much damage, but can rather take massive damage, so if a bad DPS fighter with good protection faces off a good damage dealer with lesser protection, they have the same changes, thus the system remains balanced. FO3 had a good idea, you needed a perk to be able to use PA. It was a free "perk" that everyone eventually got, but thats good since fo3 is a single-player game. In FOnline, this perk should be chooseable like other perks, so if one wants to use PA, they need to sacrifice a perk "slot". That alone should balance a bit, but the issue would remain: Everybody would gladly sacrifice any perk just to be able to use the armor instead. So the perk requirements would need to exclude those players that can be good damage dealers.
My opinion: You can argue about it all day long, but HtH players dont have, cant have, and never will have such damage output as BG/crit EW/crit SG builds. Giving PA to unarmed would be silly, but what about melee? Thats perfect imho. They could be perfect tanks up front, soaking up all the damage from HtH critters like deathclaws, while big gunners behind them deal damage to the enemy. No need to worry about burst damage, PA would withstand most of it (if the tank goes around the deathclaw so gunners have clear line of sight).
The perk requirements would look like: 8-10 Str, 6-10 Endurance, 120+% melee skill.
Ranged gunners would either sacrifice skill points in melee and be bad gunners, or just give up on PA alltogether, and be best at what they do: Deal serious damage. Not to mention having 8-10 Str would mean lower PE for example which is bad for them.
Give your thoughts about melee builds taking up the role of the tank, the perk requirements, but please...No comments such as "A melee dude killed me even tho i had a minigun." Current state of melee damage means nothing, weapons can be balanced accordingly, so if it turns out the melee+PA is OP, melee weapon damage could be lowered.
It would also eliminate complaints like BGs are costly to maintain because of ammo, and still a bluesuit with knife kills them, because PAs would be costly to maintain too.(Making a PA would be VERY expensive, and repairs for example, btw add repair npcs that repair equipment for caps)