Old armors are extremely out of date in multiple ways compared to the new gear
1. Most of the textures of older armors look like plastic and painted onto the models. Seeing that Orc and Redguard received an update to make the look less cartoony and better textured over 3 years ago, I don't see why the other base game armors don't receive a similar update. If you want players to be interested in DLC then at least make the loot in early game look as good as the DLCs.
2. Older armors do not form correctly around Beast race heads and instead just become really large helmets
Helmets on an Argonian that don't fit right
Helmets that change to fit an Argonian