Author/editor Ray Rhamey objects to authors “head-hopping,” that is, obtrusively changing the point-of-view from one character to another in the narrative. For his blog, “Flogging the Quill,” he asked an executive editor of a New York publisher what he thought about the matter, here.
Further comments from executive editor “Mad Max” Perkins, an unnamed “top New York literary agent” and others can be found here.