That means they would have to open up the APi, or recode the entire game. Im thinking that they havent done anything like blizzard did and have everything open, then lock parts down. The entire game is 'hard coded' essentially, and it would take a substantial rewrite to open it up.
If you look at wowarmory, it isnt anywhere near as simple as pulling info from a random database. If you were lucky to have an API key, you'll know what i mean.
While I do like the idea of an Armory, the devs no addon policy forbids any Api of any sort being developed and at this stage of the game I am reasonably certain they won't change their minds.