User blog comment:Aleksandr the Great/Image Tsunami/@comment-4033448-20110816070728/@comment-4058895-20110817201826

Bethesda have stated before that they have streamlined the amount armour pieces avalible. This allows the game to hold many more armour types (iron, elven, glass etc) as the engine does not have to load many armour pieces and so can hold more. This is why greaves and curiasses where merged.