I strongly disagree with making them have differences. I guess this purely depends on what you're looking for in a game. If you're looking for realism then you will hate the bikini armour, and that's fair enough.
Personally I like looking at the bikini armour, when I play a third person RPG as a female, I like to be attracted to my character, I like her to have sex appeal and admire the female form, not for other NPCs to admire her, but for my own perverted reasons. If this was a first person RPG however, I would not care as I wouldn't see my character but I do rather third person. In Neverwinter Nights I always edit the texture of the armour my character is wearing to make it more attractive to me. This is one aspect I personally like in fantasy games. I like some elements of realism, and some of sheer fantasy.
I think the only solution game developers can do to remedy this is have an option like the way you often have options for violence levels; have an option for armour revealing-ness. That way people who want to realistic armour on their female characters can have them entirely plated, and people who like to perve on their characters like me can have bikini armour.
