Recently I read an article on Azshara in Wowpedia and came across this fragment from RPG
''In a desperate gamble, the Alliance was planning to outfit hundreds of their best and brightest with the magic and technological items necessary to survive underwater. With the help of some allied makrura, they planned to stage an attack on Nazjatar. However, the attack would simply be a distraction in order to allow a small group of adventurers to enter the city, steal into the palace, overcome Queen Azshara's defenses, capture her, and return her to the surface. The Alliance plans to either siphon the captured queen's arcane powers or use her to enlist the help of the naga against the Scourge.[37]''
It's so funny, considering that Azshara could easily destroy the Lich King even from a great distance, as she did with the Pillar of Creation, but the Alliance decides to just start siphoning magic out of her and use her army in the fight against the Scourge