Get better name to replace vacuous catwalk model (3-2)
I believe the answer is:
pin-up
'model' is the definition.
(pin-up can mean a model)
I can't explain the remainder of the clue.
(Other definitions for pin-up that I've seen before include "Photographer's model" , "Poster of an attractive person" , "Attractive figure" , "Attractive celebrity" , "Alluring poster" .)