Sylvanas seems to be in agreement with her fate
"Below lies WoTLK Classic Gold the Maw," Tyrande tells Sylvanas. "Every soul that is lost in its depths, betrayed or condemned, you should search for and then send it to the Arbiter. You will toil there under Dori'thur's watchful eye. This is how you will revive your victims."
Sylvanas seems to be in agreement with her fate, saying "My actions were all mine and I am ok with the consequences" and that she will not want mercy. After numerous expansions and being identified as the game's primary antagonists , as well as committing horrendous acts that could have led to the destruction of the entire world in Azeroth, Sylvanas will be sent to the darkness of the Maw in search of the missing souls that she has sent to the Maw.
Many fans, including Alliance gamers, have been concerned about the possibility that Blizzard is looking to redeem Sylvanas and that she would be spared a proper punishment for what she did. Although she's not detained or getting the headsman's knife, having to roam purgatory for what could be hundreds or even thousands of years in search of the souls of those she wrongfully killed does seem to be an appropriate punishment, even buy WoTLK Gold if it's not the result that many Alliance players would have liked to see.
