I would suggest that Armor can be visibly or non visible upgraded using "Mission points or by adding a new High tech RW crate."
Some upgrades should include things like -
Helmet
-"Heat vision Goggles" - Counter smoke grenades effectiveness to 50%
-"Night Vision" Enhancing Stealth
-"Ear protection" Halves the effectiveness of Flashbangs
-"Mounted Flashlight" adds to lowering the stealth of your opponent.
-"Medical looks" changes the helmet into a medical looks maybe with a patch on it or a different color what also changes your name by adding a red tone or cross on it so when you fly into a different country you can immediately read the medics from the Players.
(Comes with the pro of being faster seen but also probably targeted by muggers)
Body Armor
-"Chainmail layer" (What german police uses)
Bonus against slashes, stabs, fragmentation "Grenades, piercing 10%, slashing 20%" may with a debuff of -15% Dexterity."
-Ammo pouches / bandolier
Extra ammo or extended mag just like the weapon mods. Or as a buff for machine gunners
-Medic upgrade" Including just like temporarily weapons an extra slot for medical items and be usable for group attacks to heal someone in your team using (Morphin, Medkits, Bloodbags"Maybe even Adrenalin") so even if you're too weak to participate you still can help your teammates out) it should also come with an visible Medic Armband cross.
-Ballistic Collar "Protecting around 50% of your Throat with the same protection rating of your current body armor
-Hydration bag with drinking tube, can be filled with energy drinks and used once in a foreign Country when traveling (useful for Medics, War)
-Ballastic Groin Pad (Explains itself)
-Heat resistant layer "Molotovs, flamethrower damage"
two attachable modifications should be allowed just like the weapons but I am unsure about the helmet.
So far it's just an idea but after seeing so many requests for medic armor, I thought to myself "Why not include everyone?"