What's acceptable re: DOF

In many types of photographs, I feel complete depth of field is essential.  This includes landscapes, most macro photos, patterns, and architecture shots.  For wildlife and birds, we have to use long telephoto lenses, and in these cases shallow depth of field works well because the subject, like this wild dog from Namibia, is isolated, emphasized, and stands out against the background.  But what about the nose and ears that aren't sharp?  In my opinion, the ideal would be to have both of these areas of the animal's head sharp.  However, given the nature of optics, we have to accept less than sharp areas like this if and only if at least one eye is sharp.