Missing Caster Cloth Donor items?

[Dingdong]

Wondering why some pieces aren't available from the donor vendor.
Dark Conjuror's Collar (http://www.wowwiki.com/Dark_Conjuror's_Collar) isn't available but the Mail equivalent (Cowl of Gul'dan - http://www.wowwiki.com/Cowl_of_Gul'dan) is there. Both items are the same ilvl.

Also wondering about Handguards of Defiled Worlds (http://www.wowwiki.com/Handguards_of_Defiled_Worlds), as other equivalent ilvl gloves and similarly itemized gloves are available.

For completion's sake there's also Fel Conquerer Raiments (http://www.wowwiki.com/Fel_Conquerer_Raiments) but the Robes of Ghostly Hatred are already there.

[Wacco]

KJ items :(

also the conq robe was in ZA for a long time

[Dingdong]

There are quite literally pages full of KJ items from the donor vendor though. What does KJ have to do with it? I understand some weapons are intentionally left out.