They had a system like this in Daggerfall I believe. I wouldn't care either way if they used it though.
You are right, however a pretty low level mage could identify them himself.
The mage guild could identify for 10% of the items cost. However the value of the item was known, if it was low the enchantment was probably junk, if it was high you could sell it if you didn't like it.
As I understood this was a misunderstanding in Skyrim. In Skyrim you will not know that you get as quest reward for many quests. In Oblivion you got a levelled item, I guess you get a fitting item from a list in Skyrim. So if you do a quest at level two you get an named iron or steel sword with a low enchantment. at level 40 you get an named ebony sword.
Because the quest giver don't know that he gives you he will not say that reward is.