Covering everything is only part of the requirement. The other part is how do you doff the suit without creating a path to infection, and what is the possibility of mistakes in doing so. With two gloves, the outer one is presumed contaminated. So, you cannot use it to remove the mask and goggles without risk of contaminating your hair. You remove the outer glove, leaving a presumably clean one. Then you remove the suit touching only the inside and the ties. Are the ties infected? A mistake or bad luck there contaminates the inner gloves. Hence the third pair, or multiple disinfectant rinses (as in the Africa video), may be needed to remove the goggles and face mask safely.
The CDC guidelines I have seen really do not account for all of this. So, to me, the CDC guidelines seem to be inadequate.
The University of Maryland / University of Nebraska guidelines for doffing seem to be rigorous. I especially like having two pairs of gloves for the hazmat suit and, after the coveralls and inner gloves have been removed, donning a 3rd, clean pair of gloves, before doffing head gear. The other guidelines, CDC and WHO take shortcuts, like using only one pair of gloves. I wonder why? Are these shortcuts the reason that the Texas nurse got infected?
Something else I just noticed is that the University of Maryland suit does not include a hood, and the UM procedure does not disinfect gloves in the chlorine solution between steps, whereas the MSF / LIberia procedure in the video linked below uses a hood and a chlorine solution. It looks to me like the UM face shield has more gaps or pathways to infection than the hood.