In Oblivion there was a Daedric Invasion occuring so the fact that Daedric Armor could easily be found is believable to me although the amount of it in Cyrodiil was still a bit much for my taste. Why shouldn't there have been tons of Daedric Armor available in the planes of Oblivion?
Lore-wise, there shouldn't really be any available there though. The "daedric armor" worn by the invading dremora isn't really armor but actually their skin, and the fact that it could be looted in some instances in OB was probably just an oversight.. From one of the in-game books:
Regarding Daedric Armors and Weapons, these items are made from raw ebony, which has been refined using the craft and magical substances of the lesser minions of Oblivion. The process is not a pleasant one for the Daedra involved, and these items retain echoes of preternaturally prolonged suffering endured during manufacture. Daedric Armors and Weapons are the most rare and expensive armaments known in Tamriel.
Back on-topic, I'd really like if it was almost as rare as in MW, possibly 2 sets or so though with various ways of procuring it, such as for example at the bottom of the hardest dungeons, end of difficult puzzles and mazes, to be stolen from rich nobles etc. I also hope they have differing helmets as in MW, think there were 3 or so different models to collect iirc? Another option would of course be to let us collect all the materials and have some legendary blacksmith and enchanter create say a headpiece for us ^^