IMO the lessons learned from the Zombie idea are: It is not enough to restrict the discussion about consciousness on the physical components of the organism. One has to consider also the aspect of information processing in the organism. Information processing is not a static structure but a dynamic process.
The investigation of the processing of stimuli in the visual field V1 and subsequent cortical fields, i.e., the corresponding cortical wiring diagram, is a main task in the study of the neural correlates of consciousness (NCC).
I do not know whether the concept of a Zombie as being “exactly like us in all physical respects but without conscious experiences” is helpful to stimulate further research about NCC.
Possibly the concept is already too coarse for the present level of research in neuroscience.