I looked around in wowmodelviewer because i noticed that some of the ICC 5man gear is nexus themed.
after i noticed that lurked around for the old collections of weapon models that were released pre-Wotlk for wotlk.
apparently there was supposed to be another (or longer) nexus raid along with a Drak'tharon keep raid.
Im actually really depressed that they were never implemented and only about 1/4 of the weapon models are being used in other raids that dont fit the theme
Naxx, sarth, and the new ICC 5mans all use some weapon models intended for the nexus and drak'tharon raid.
All if not most of the weapon models for those nonimplemented raids look incredible (im a guy who actually liked Zul'gurub and Zul'aman art) and the rune/icy theme of the nexus gear really shows the blizzard design team's creativity and artistic skill.
Im optomistic so maybe they will release a drak raid with the release of Zandalar and the troll leaders. idk