I'd say Skyrim's armor is better than Oblivion in nearly every case. There are just a few things I don't like. One is the Steel Plate helmet, but it's much better with the open-face mod. Looking back to Morrowind I'd say it has dibs on glass, I also really like the Morrowind Orcish armor. I miss all the weird tiers from Morrowind, like Bonemold, Chitin, and Trollbone, all those odd pieces that either didn't have full sets, or were variants on a set. They did that do a lesser degree with the lower tiers in Skyrim.