I wonder if you have ever seen photographs of women wearing full late-medieval plate armor.
You may notice that when women wear these outfits, they tend to look the same as men do in them. This is because the protective design of plate armor -- sloped breastplate to deflect blows, articulated skirt, pauldrons, helm, gauntlets, etc -- winds up obscuring the shape of one's body. While the armor does require measurement adjustments for wider hips and narrower shoulders, it's hard to notice the difference at a quick glance.
Artwork of women in armor may emphasize certain female-bodied qualities to make it clear that yes, this is a woman in armor. But when a real-life person wears genuine medieval armor, when they gather up their hair out of the way and put that helmet on, you'll have a hard time telling if the person inside is a man or woman. What's more important is that they're wearing a big steel can, they've got a big sword, you're wearing hardened leather and you've got a hammer on a long pole and you have to figure out how to get the nasty part of your weapon into a spot in the armor that's vulnerable, within the next two seconds.
Now, I have read a bit on the subject of female armor being portrayed realistically in artwork. The writer of the article points out out that the way armor is presented for women is unrealistic, because the classic "boob plate" would frequently direct hammer and sword blows right to the middle of the chest, and there goes your sternum, CRACK.
But in the realm of artwork realism is less of a concern to me than symbolism and genre expectations.
Art, after all, is meant to influence, and one measure of a piece of art is how it influences people, and how well it does so. What something LOOKS like is more important that whether it could be ported to the real world.
To a certain extent, boob plate armor in fiction and video games looks to me like -- a woman wearing armor. She's a knight, she charges into danger, fights dragons, that kind of thing. Power turned toward the good. Her armor fits the genre of sword-and-sorcery stories. If she's wearing a suit made all of metal, then the implication there is that she's a fighter. And I like that. After Anglo-American culture suffered 180 years of bullshit about "women are inherently more delicate than men", it's nice to see a recent shift towards equality. Women in fiction are increasingly included in the position that Anglo-American culture considers the highest ideal of noble, individualistic might in the realm of fantasy: The Knight.
My only quibble is that it would be just as easy to draw a female knight with helmet off and long hair waving in the breeze. While it would be equally unrealistic in terms of a battlefield, it would be less annoying to my highly prudish sensibilities than Boob Plate. What's worse is when you've got female warriors having incredibly low necklines on outfits that are supposed to be heavy armor. At least Boob Plate looks like plate armor; low necklines look like someone took a shirt from the mid-2000s and drew details on it to make it look like armor. At least she's wearing armor...
And then there's Battle Bikinis.
These particular outfits, as exemplified by Red Sonja, are frequently derided on the basis of their complete disconnect from the reality of battle. Other people counter that, while the sexual nature of the armor is obvious, this is a selling point for many women because sex is empowerment.
I can imagine that the ability to write and draw female characters in charge of their own sexuality is a point of pride for people who feel like they are weighed down by a heavily censorious culture. To create To create a character who can charge into battle nearly nude, and yet survive, is a common visual symbol of the character's battle prowess. Thus Conan the barbarian fights wearing nothing but a fur loincloth, and the Celtic warriors of ancient Britain fought nude, and Frank Miller has his Spartans fighting completely naked. To create a female character who can do the same thing might be, to an artist, a way of getting women into this visual genre the way Boob Plate armor gets women into the Knightly genre. As a matter of fact, Red Sonja was created with this idea in mind: to be a female counterpart to Conan. She first appeared IN the Conan comics and she's based on a character Robert E. Howard wrote in 1934. She's called "She-devil with a sword." She's supposed to be a roaring barbarian, with a skimpy outfit because that's what the Conan barbarians wear. To the artist who drew her first appearance in the 1970s, she probably looked like Female Empowerment in a feminist era.
And yet, there may be a disconnect between what the artist sees and what the audience sees. Heteronormative Anglo-American culture has long been conditioned to view men and women differently when they have their shirt off: if a Man does it, it's because he's working, if a woman does it, it's because she's having sex. So a man can charge into battle wearing nothing but a loincloth, and he looks like a barbarian warrior, but if a woman does it, most of the men in the audience are not thinking of her battle prowess. There is already a visual genre that features a lot of nude women, and it has nothing to do with battle.
When you have a young, leggy, busty woman wearing naught but a chainmail bikini and charging into battle with a sword, two genres collide: war and porn. And the porn part tends to win out visually unless your particular fictional battlefield has lots of blood and guts flying everywhere making everyone look gross and scary. Most artists tend to leave out the blood even in stories where you've got swords waving everywhere. So a woman wearing a Battle Bikini looks like sex on the battlefield, and this is absurd: sex is what can lead people TO wars, but doesn't work on an actual battlefield. Sexiness does not apply there. There's no space for a quickie behind the battlements in a story where everyone is supposed to be fighting for their lives.
Not that some artists shy away from absurdity. You could write a story where war and sex were the same thing, or where sex was considered a weapon of the battlefield. "Oglaf" does this all the time. The writer makes a joke out of the war genre and the sex genre all the time, sometimes at the same time.
Barring the extreme nature of series such as "Oglaf", one can still create a story where war is taken less than seriously. It is entirely possible to write and draw a story where men and women alike wear skimpy outfits or big suits of armor as they please. The difference in outfits can be portrayed as one of Speed Versus Endurance, or some similar contrast. The question then becomes -- how many women are wearing the skimpy outfits versus the heavy armor? What about the men? What implications arise from the ratio of Battle Underwear to heavy armor?
How many stories exist besides League of Legends, where you have a mix of women and men waring heavy armor and skimpy outfits? I shall have to find out.