Needs More Examples
There are many,manyways of making the difference between heroes and villains obvious. One of the many tricks consist in making a villain or more wearing armor, while the heroes facing them don't.
One of the main reasons is making said villain a Tin Tyrant, but there may be other possibilities behind it:
The villain's power relies on said armor, forcing the heroes to find a way around to hurt him.
Is a subtle way to imply that the hero is better, because he doesn't need any further protection.
The Saiyans in early Dragon Ball Z wear some sort of armor, as do Freeza's soldiers later, in contrast to the Z Fighters who mostly wear martial arts gis.
Vegeta in his long transition from villain, to anti-hero, to hero wears less armor every time he gets a costume change, from his first appearance with a battle skirt, winged shoulders, and a scouter, to the Buu saga with no armor at all.
In One Piece one of the most memorable examples would be Luffy versus the weapon-loving Don Krieg. A good part of the fight revolved around Luffy trying a way to break his armor.
Yaiba vs Takeshi Onimaru, after the latter is possessed by Fujin.
In Fairy Tail we have most of the guild members against Master Hades, while earlier, we have Sugarboy vs Gray. In the latest arc, the Raven Tail flagbearer (Actually Ivan in disguise) is completely covered in armor.
In Rurouni Kenshin, Fuji at first wears a set of armor as he faces Hiko, but when he's told that wearing it will only boost his confidence and make his attacks weaker, he decides to opt for a fair and square fight, and removes it.
In Gamaran none of the Ogame Ryu members wear protective clothes of sort, while many of their enemies may usually wear chainmail of sorts to protect themselves.
Hanaukyō Maid Tai La Verite. In episode 11 Konoe Tsurugi's Onee-sama wears a heavy armor suit in combat, while her opponents Konoe and Yashima don't.
The invading aliens from Independence Day have deflector shields on their motherships and fighter craft alike. This renders them invulnerable to Earth's weapons.
In Journey to the West, after starting the eponymous journey with Tripitaka, Sun Wukong wears nothing but a tunic and a tiger pelt used as a kilt, and being monks neither Pigsy or Sandy carry armor. Most of his opponents will show some impressive armors, helmets and plates, usually described in high detail. Of course, that doesn't help them much.
In Doctor Who, the Doctor and his companions are always wearing normal Earthly clothing, while monsters like the Daleks and the Cybermen are heavily armored.
Warhammer 40K: Both Space Marines and Chaos Space Marines use armor, but the CSM's is the Obviously Evil kind, decorated with skulls and spikes and sometimes demonically possessed. By contrast, the Imperial Guard has flak armor, referred to in fandom as "T-shirts" to emphasize just how badly the Guard is equipped.
In God of War we have Kratos, who's almost always wearing a loincloth and sandals against the heavily armored Ares. The third game pit you against two notable armored bosses: Poseidon and Hercules. In both cases you have to smash the armor first.
In Final Fantasy II, Firion and co. wear civilian clothing, and only one of the temporary party members wears armor. The Evil Empire's mooks and Dragon all wear heavy plate armor.
Golbez of Final Fantasy IV is a Tin Tyrant, while only two out of the twelve members of the player party are armored (Cecil and Kain). Cecil also loses some armor coverage when he transforms into a Paladin, although he's still clearly a knight.
In Final Fantasy XII, the main party are wayward members of La Résistance who spend a good chunk of the game fighting Archadian Judges, powerful warriors armored head-to-toe to enforce the will of the Empire. The main party sticks to normal clothing, which only includes a couple of token armor pieces if any.
The robot probe sent by Gallaxhar in Monsters vs. Aliens has deflector shields that render it invulnerable to the Army's weapons. The five monsters battle the robot without armor or even weapons. Ginormica puts up a goodly tussle, and Doctor Cockroach is, of course, unkillable.
Inverted with the armored conscripts that defend Imperial China from the armorless Mongol horde in Walt Disney Pictures' Mulan.
The Urpneys from The Dreamstone wear metal armor and helmets (they also wear swords on their belts that are never used in combat). The Noops Rufus and Amberley are completely unarmed children (though Rufus has a similarly underutilized sword in the first season) and the magic powered Wuts are completely naked. Both of the latter groups suffer much less to slapstick injuries than the Urpneys despite their armor.
Ben 10 versus the Forever Knights. Ben transforms into different aliens, but none of them really have armor. Gwen and Kevin count in the sequels. Kind of.
Teenage Mutant Ninja Turtles: The Ninja Turtles only have shells, and many of their allies are completely unarmored, but Shredder is heavily armored.
Five hats means that five tropers think it is ready to publish.
You are saying that you think this draft is ready to be published. That means the description is not ambiguous,
it doesn't duplicate an existing trope, there are at least three examples, and the title makes sense.
Is that what you meant to do?
You are saying this draft has a ready-to-publish hat it does not deserve and you are taking it back.