The anchoring job of the evening news is still the most prestigious job in American journalism, certainly in television journalism. It is the pinnacle.
If they keep Charlie in the morning, what they're saying is, we don't want to run the risk. If they take Charlie and put him in 'World News Tonight,' that's a statement that the flagship show is still mightily important.
My sense is that her identity has been so associated with the morning news format that it will be difficult for her to make that transition and have the same kind of dominance that she enjoys in the morning.