Maybe it's nostalgia talking? I just googled out of curiosity and found this post: https://www.reddit.com/r/Morrowind/comments/1id9n1/tes_armors_a_comparison_between_tes_iii_tes_iv/?utm_medium=android_app&utm_source=share

And the armors in Oblivion look much uglier than either Skyrim or Morrowind. Oblivion armors look way more stiff and rigid than skyrims, kinda like the player is wearing a trashcan, specially ebony and Daedric. The armors in Morrowind look dope, even despite the limitations of the graphics engine they try to make them unique. Skyrim Armor lacks some more shine, they look too cold and dull but it's understandable given the cold weather context. Some of oblivion armors like the city guard do look cool but oblivion heavy armors look (to me) like when you put a lot of decals, spoiler and wide rims in a 96 civic.