They mentioned in one of the feature articles something about seasons, and having some sort of survival aspects in the game. I think this could be used as an interesting mechanic to help balance things. Say, for example, you're in a cold environment or it's winter, it may not benefit you to equip the highest defense armors because they maybe they don't keep you warm. They already mentioned also that each season would be a week long, so if the seasons had an impact on what sort of armor you could wear, it would push people to have to change their builds on an almost weekly basis just to account for the weather.
