In real life, women tend to wear more revealing clothes than men do. Why should this be any different in a fantasy RPG? Of course, there should also be non-revealing clothes for women.
In real life, it's generally a bad idea to walk into combat unarmoured (though you could also call it "heroic"). In a game world, characters can usually take a few hits before they are killed. There is magical healing, and regeneration can be very quick. In the context of this different reality, characters might not deem it necessary to wear armour, even if there isn't a fighter companion (or pet) who can act as a "doorstop" for enemies.
Wearing partial armour when you can have full armour is a bad idea, agreed. Having boob cups on armour is dangerous, true. But it's just as stupid to wear a heavy spiked shoulder piece that imbalances your movements and obstructs your sight. However, some people don't seem to care because they think it's cool. And the game developers cater to their wishes. As long as there also is some non-revealing and some non-exaggerated armour, everyone should be able to choose their character's looks as they see fit.
I also prefer more realistic armour than is depicted in the Original Sin concept art. But who am I to say that only my preferences should count when there are obviously players who want revealing or exaggerated armour?
