Vicious unlock quest are a good idea. But the quests are only accessible after Horratio goes down. Something like beating the previous level with 4 characters (and remove Vicious HoS, and move vamp quest to Namtar)
The Master: You stopped the threat from the east, and their master has retreated. If you want to reach, and kill him, you will have to go through The Indomitable...
Demonic Rituals: The changeling demons have been stopped and their essence has sealed in the demonlords. If you wish to finish them once and for all, you must collect more essence to reach their Demonic Library.
The Last of the First: You have eliminated the Druid threat in the west, and the dragons fled through the underground labyrinths. While they pose no threat and your western borders are safe, it might be worth pursuing. Unfortunately, that requires more exploration the labyrinths.
A Game of Kings: Due to the killing of the high general Issstama Itsssa, the Naga Empire has backed off. Still, their actions were unacceptable. If you wish to find their Kingdom and take vengeance, it will require further searches into the swamp.