Its seems that the Old Kingdom is what used to be of the nerubians when Arthas trekked through and such. Azjol Nerub is like a current housing, living area maybe?
But when you drop down the hall you fall through ALOT of "old kingdom"
There has to be a raid scheduled for this somewhere, it wouldn't include anyone important that we know of, unless Anubarak comes back to life somehow. We aren't strangers to seeing that though. Id like to see a giant old kingdom raid, even though I despised Old Kingdom lol