Duck, I think I somewhat follow you now, but I think you misunderstand what I'm trying to say, or even what this thread is about. 
First, all your talk of Mab's mantle seeing all possibilities & constantly reevaluating itself has nothing to do with nature.  Nature, as I define it, are hard wired imperatives that the mantle pushes on the bearer.  Mab's mantle pushes cool logic, Titania's pushes emotion.
Winter Knight, as you say, is that of a violent idiot.  
But the point of this thread, is that Harry has other mantles, & at least immortals can change a mantle on Halloween with bits & pieces like this.  So for Harry & subsequent Winter Knights, the imperative might not be that of a violent idiot.
In the case of Mab, if her nature were to be changed, she might become more emotional & not be as closely tied to the embodiment of what is Winter.  To stop always thinking so logically & embrace other ways of thought.
That kind of change would require actively tinkering with her mantle & bringing in new parts.