The Deathknight just wouldn't be the same without the trademark armor.. or something.
The Deathknight automatically gains points to his armor rating as "he" levels up and it is dependant on the difficulty level. There are no base stats for the individual pieces.
The Deathknight generally has a lower armor rating than your character if you try to keep up your character with decent armor.
The Deathknight will not gain much learning armor because his armor doesn't absorb damage.
