Sometimes I think about bikini armor, and it's not for the usual reasons.
I grew up on Larry Elmore and Clyde Caldwell art, which has no doubt stunted my development as a man, and they were both fond of the occasional plate bustier and pointy loincloth. Then I ostensibly grew up and ended up in the games industry, where I occasionally get half-clad pixel tits not so much shown to me as launched into my face at high speeds. It's not as good/bad as it once was in that regard, but the tendency still exists.
Obviously the reason behind bikini armor's to attract men (and interested women) to the product and/or service. It works very well in so doing, even if the product and/or service is a complete dumpster fire. (
Something got
Witchblade through 80 issues before Ron Marz showed up, and it was
not the intricate, careful historical drama.) Anything else you hear is generally a hasty excuse made by some dude who doesn't want to admit that the real reason is either "Because it sells" or "Because I
really like tits."
That said, within the context of a story, I sometimes wonder about the women in bikini armor. The out-of-story rationale for their outfit's obvious, but in-story, you rarely see it even addressed.
The first character that comes to mind here is the protagonist from Billy Tucci's
Shi. The title character's main personal struggle is in reconciling her mother's Catholicism and her current violent existence as some weird modern samurai, killing the shit out of all sorts of random ninjas and monsters, but at no time does she even bring up the fact that she's almost naked from the waist down. It's as if the whole "almost naked" thing is incidental to the process, or at least unworthy of discussion; yeah, of
course modern samurai/ninja cross-class fighters go into battle without pants. Don't you know anything about Japan?
Sometimes a dude takes a swing at it, and it's obvious he's not trying. That's when you get the mobility excuse, or how agile the character is because she isn't weighed down by heavy armor. Granted, even the best in-story explanation for the character going into a fight half-naked is going to be interpreted by the audience as "I like naked women," so there's no reason to bring your A-game.
Just the same, sometimes I think about characters as if they weren't fictional, and there were no considerations given to their attire that came from anywhere but themselves, and towards that end, I wonder about the rich inner life of the woman in bikini armor. They generally aren't the kinds of characters who would put up with nonsense, so you have to assume they
want to be wearing what they're wearing, which leads to the question of why.
You could go with the cultural excuse; they're from someplace where
everybody dresses like that. Edgar Rice Burroughs's original
John Carter of Mars books could not be filmed as they were written without an NC-17 rating because nobody, male or female, was wearing much more than bikini briefs. The Dynamite Comics version of Dejah Thoris, as salacious as her covers might seem, is considerably
more modest than the source material. By the same token, Red Sonja's scale-mail bikini may be her typical look now, but somewhere along the line her comics forgot that she wasn't supposed to be the only person wearing one.
There are a handful of characters who draw power from nudity, like the chick from the
Oneechanbara games, who gets stronger based on how much blood's touching her skin, or Purgatori. Conversely, you get Adam Warren's Empowered, who ends up half-naked a lot of the time because she has a powerful super-suit that's also surprisingly fragile. (That said,
Empowered is explicitly a parody in a lot of ways and isn't quite as useful to the project, since it's
supposed to be fucking ridiculous.)
Another example I always liked was Alias, from the Forgotten Realms novel
Azure Bonds, who had a suit of magic chain mail that happened to leave most of her sternum bare, but which explicitly protected that area. People kept trying to stab her there and being surprised when the blade skidded off.
Finally, there are the characters who are invulnerable, so it doesn't much matter
what they wear. Vampirella might count here, although her weird slingshot bikini's looked pretty silly for a long time now, or half the superheroines you care to name. A female vampire might go ahead and take advantage of club wear or other trends that let her go out half-naked, because she's likely to get shot repeatedly anyway. At least, that's the justification that I assume the current Dynamite version of Chastity Marks is using.
It's an interesting challenge, or it could be: come up with a character that happens to be scantily clad, but figure out a way to make it so either nobody notices or everyone's fine with it. I'm pretty well convinced that the bikini-armor lady (or her modern equivalent, the woman with an inexplicably bare midsection) isn't going anywhere, because she's still a really good way to get that 15-28 male demographic to buy your shit, so the only real way to deal with it is to bring the thong-plate dude into circulation.
I'm sorry if that becomes a thing.