Under those rules, I can understand that the game world is not realistic, so non-realistic armours are okay.
"Realistic" may be the wrong term in a fantasy RPG, but the armour style should be "credible", i.e. the player should think that a piece of armour both fits into the world and does its job. Of course, credibility largely depends on the player's background, so there is no "right" way to design armour.
But that isn't the conclusion, and even if it was we're going down a path that isn't relevant. I'm not arguing about the *type* of armour, I'm arguing about the *design* of the armour. Plate offers the best protection, but at the expense of mobility and how long you can fight for. If you go down in full plate, you're screwed.
Oh, it is relevant. If you accept that armour isn't all that important for surviving combat in the game world, you can ask yourself which motivation one might have to still wear it. One can reason, for example, that armour is only necessary where being hit really hurts or where scars would be particularly undesired. And that's a possible explanation for wearing a helmet plus an armour bikini or "metal trunks".
That doesn't mean I want bikini armour, but it shows that it's not necessarily completely irrational to introduce it into a video game - though I doubt this has ever been the motivation behind creating bikini armour. And it wouldn't explain why men wear full armour when women wear bikini armour ... perhaps men are more fretful than women after all
They are a way to achieve that, but they're not exactly the best way. You compare the models in Div 2, and there's a clear difference in the builds of the characters. You can use animations, height differences, different models (e.g. wider hips, narrower shoulders for female). That's what Skyrim uses. Many of the armours are fairly neutral but you can tell the differences (and there's really only one plate 'boob armour').
Armour with boob cups isn't the only way to achieve that, right, but it is very easy to notice. When armoured NPCs are just standing around, animations won't necessarily indicate their gender. Both men and women can be tall or short. Wider hips and narrower shoulders can more easily be missed than boob cups.
Who knows? I don't think it's a demand issue, it's more a social one. If you look at fashions, men's clothing tends to cover, women's tends to reveal. You get the idea. But there's no real reason to reveal anything. Even just some cloth padding can be useful as armour.
I think demand plays a role. If a sizeable percentage of the target group wants revealing female armour, but almost nobody wants revealing male armour, the latter won't be implemented.
Anyway, women aren't forced to buy and wear revealing clothes, are they? If many still do it in the real world, it's not unreasonable to assume that many do it in a game world.
