Ranked armor is a great idea, but I believe there is more room to grow making other types. I also suggest the introduction of specialty armors that focus on certain aspects of combat. Some suggestions are:
Ranked Armors (similar to sentinel but focused on other specific stat):
Bionic Armor: increase strength bonus
Marksman Armor: increase speed bonus
Stealth Armor: increase dexterity bonus
Speciality armors (armors that specialize in a specific type of combat), could be tagged as gold quality gear:
Exoskeleton: chance to increase hand to hand accuracy and damage, increase critical chance and damage at the beginning of the fight. 1% Motivation chance, all stats increase (strength, defense, speed and dexterity), very light coverage and armor. Must have all pieces on to have bonuses. 1% chance of ko, automatic win. Can't use weapons.
Assassin Armor: killer, 1% chance for backstab, and apply bleeding and poison on successful hit. Chance for increased dexterity, speed and stealth bonus at the beginning of the fight, light armor. Bonus to poison damage. 1% chance to apply poison to melee weapons and bullets at the beginning of the fight. Small chance of ambush (going first while on defense) Must have all pieces on to have bonuses. Can only use light weapons (melee, secondary).
Mecha Armor: chance for increased damage, accuracy, critical chance and critical damage to heavy weapons and machine guns, give extra rd to Heavy weapons at the beginning of the fight. Heavy armor and coverage. 1% of indestructible , chance of no receiving any damage. Decreased dexterity and initiative. Can use only heavy weapons and machine guns. Must have all pieces on to be usable.
Hitman Armor: chance for increased accuracy, damage and stealth using rifles, pistols and small machine guns at the beginning of the turn. Small percentage of going first in defense while using those type of weapons. 1% chance of lethal shot (expose and deadeye at the same time). Medium armor and coverage. Must have all pieces for bonuses.
Warrior Armor: chance for increase accuracy, damage, critical chance, critical damage and stealth while using melee weapons at the beginning of the fight. Ultimate parry 1% of parrying any attack. Small chance of initiative while on defense using melee weapons. Light Armor and coverage. No bonuses for for weapons that are not melee. Must have all pieces for bonuses.
Cowboy Armor: chance of increase damage, accuracy, critical chance, critical damage with shotguns, revolvers, whips (and any other weaponry associated with cowboys) at the beginning of the fight. Small chance if initiative while on defense, when using the cowboys weapons. Gunslinger, 1% chance to get off a shot before the opponent when it's the opponent's turn with critical damage. Light Armor light coverage. No bonuses for other weaponry. Must have all pieces for bonuses.
Also, you could make hybrid armors that combine different attributes of other armors, but less effective. It will give more room to play certain builds, and more versatility for players to choose.
Ranked Armors (similar to sentinel but focused on other specific stat):
Bionic Armor: increase strength bonus
Marksman Armor: increase speed bonus
Stealth Armor: increase dexterity bonus
Speciality armors (armors that specialize in a specific type of combat), could be tagged as gold quality gear:
Exoskeleton: chance to increase hand to hand accuracy and damage, increase critical chance and damage at the beginning of the fight. 1% Motivation chance, all stats increase (strength, defense, speed and dexterity), very light coverage and armor. Must have all pieces on to have bonuses. 1% chance of ko, automatic win. Can't use weapons.
Assassin Armor: killer, 1% chance for backstab, and apply bleeding and poison on successful hit. Chance for increased dexterity, speed and stealth bonus at the beginning of the fight, light armor. Bonus to poison damage. 1% chance to apply poison to melee weapons and bullets at the beginning of the fight. Small chance of ambush (going first while on defense) Must have all pieces on to have bonuses. Can only use light weapons (melee, secondary).
Mecha Armor: chance for increased damage, accuracy, critical chance and critical damage to heavy weapons and machine guns, give extra rd to Heavy weapons at the beginning of the fight. Heavy armor and coverage. 1% of indestructible , chance of no receiving any damage. Decreased dexterity and initiative. Can use only heavy weapons and machine guns. Must have all pieces on to be usable.
Hitman Armor: chance for increased accuracy, damage and stealth using rifles, pistols and small machine guns at the beginning of the turn. Small percentage of going first in defense while using those type of weapons. 1% chance of lethal shot (expose and deadeye at the same time). Medium armor and coverage. Must have all pieces for bonuses.
Warrior Armor: chance for increase accuracy, damage, critical chance, critical damage and stealth while using melee weapons at the beginning of the fight. Ultimate parry 1% of parrying any attack. Small chance of initiative while on defense using melee weapons. Light Armor and coverage. No bonuses for for weapons that are not melee. Must have all pieces for bonuses.
Cowboy Armor: chance of increase damage, accuracy, critical chance, critical damage with shotguns, revolvers, whips (and any other weaponry associated with cowboys) at the beginning of the fight. Small chance if initiative while on defense, when using the cowboys weapons. Gunslinger, 1% chance to get off a shot before the opponent when it's the opponent's turn with critical damage. Light Armor light coverage. No bonuses for other weaponry. Must have all pieces for bonuses.
Also, you could make hybrid armors that combine different attributes of other armors, but less effective. It will give more room to play certain builds, and more versatility for players to choose.