I recall the devs sayin that the Underdark is/can be/should a part of Act 2. So if the Hag will return, maybe will do so thru her portal to the Underdark
On the other hand, if you take Underdark route to those moonlight towers (or something like that) is seem pretty obvious, it would be incredibly sad if in Act two underdark contained only stairs to surface. -_-
I still dont understand why cant we change Race for our hirelings. Lets us play Githyanki as racist as they trully are!