*cough* *cough* ... your avatar.
I know, right? And now that I have your attention...
But along that same line of reasoning, you also cannot prove that the same suit of armor for both genders is noticeably skimpier on the female in this game. So we are at an impasse.
I don't know how many different pieces of armor one can equip at the same time, and http://1.bp.blogspot.com/-QIGO3XUZHe8/T6iZPxHbxEI/AAAAAAAAAIA/npPbG5YowZY/s1600/ElderScrollsOnline02.jpg is old so the design may have changed, but to me it looks like the Orc and the Breton are wearing the same type of armor. But I won't be 100% certain until the Beta-testers confirm this, so you're right.
However, for the sake of discussion, if I had to guess, I would say that those two concept arts of the females showing a bit of skin are probably light armors and I'd be willing to bet that the male versions of those armors are also showing skin (they don't exactly have cleavage to show but you could probably see their neck/arms and maybe some of their chest).
I'm okay with light armor being more revealing, it is after all designed with mobility in mind (if not scarcity in materials is the case).
But the armor in the picture I linked looks like heavy armor to me. Again, I don't know if the pauldron comes with the armor or not.
I wouldn't be so alarmed about this if not for the frequent display of boob windows in the artwork and preview footage. I hope it won't be the case once the game comes out.