Blackwing Lair

Blackwing Lair is still quite deadly in recent run today, as a lot of players are defeated by Shadow Flame during the following encounters: Firemaw, Ebonroc, Flamegor and Nefarian. The dots are still powerful even if the players are level 80. Luckily, this can be avoided easily by wearing Onyxia Scale Cloak or learning the fights.

Lastly, although the attunement has been removed, completing Blackhand's Command will give you access to orb that can teleport to Blackwing Lair.