I have one last achievement to acquire the mount. It’s been a year that I keep trying to get IC to work again. I have tried letting fights last a long time letting all dialogue cycle through, resetting instance, running around killing everything in sight.
Each run I make sure to kill every boss as it shows it in the Raid Info. The teleport in the center does not work. There is no way for me to kill the final two bosses Queen Lana 'Thel and Lich King.
Another note, it does not have an X on the map for Valithria Dreamwalker even though I healed her and looted the chest.