Hmm well if you take steel away which you get up both trees (yah I know it is a heavy armor with the addition of plate) you get four types you can craft up each tree. I understand how you feel though light armor doesn't really do it for me eithier.
There is lIron, banded Iron armor, imperial heavy armor, Steel, steel plate which for sOME REASON is on the light side, dwarven, orcish, ebony, daedric, and dragon bone, oh yeah and ancient nord armor. with LA you have hide, studded, imperial light armor, leather, elven, scaled, glass and dragon scale, 4 more options for the HA, if they all had light and heavy variants, there would be more variation, cuz each variant would look different, light daedric and heavy daedric would look completely different.