"But I don't feel that this plan is very reliable," Hircine's madness stems from his own curse, the weaker his power, the clearer his mind becomes. A rational Hircine would never emerge to bear the wrath of the Lord of the Dawn. The end result would only be Hircine firmly grasping his deity position and hiding away, till the end of time, until I, this mortal, perish under the torment of fate."
Amberser never felt that he had escaped fate, on the contrary, he was constantly provoking the bottom line of this goddess, knowing that one day it would not be the Goddess of Fate stepping on him, but rather that he would completely escape fate and become a new deity.
And by that time, he might not become the new Prince of Lies, thus smoothly sidestepping the trouble Amberser presented.