Honestly I think oblivion might have had equal or less, vanilla to vanilla.
Less, like, considerably less. I'm only going to count sets that have at least a unique Body, no artifacts in either case.
Base Vanilla Armor in Oblivion.
Fur, Iron, Leather, Steel, Chainmail, Dwarven, Mithril, Orcish, Elven, Ebony, Glass, Daedric, Arena L. Arena H, Blades, Shrouded, Imperial Dragon.
Base Armor in Vanilla Skyrim:
Fur, Hide, Studded, Leather, Elven, Scaled, Glass, Dragonscale, Thieves, Imperial Light, Penitus Oculatus, Stormcloak Officer, Nightingale, Shrouded, Forsworn and Guard*. And that's only the Light Armor.
Iron, Banded Iron, Steel, WolfSteel, Dwarven, SteelPlate, Orcish, Ebony, Daedric, Dragonplate, Blades, Imperial Heavy, Ancient Nordic and Falmer. That's the Heavy list.
*Guard Armor is the Cuirass, which Varies, and the unique Fur boots/Gloves/Helm that guards/stormcloaks wear.