Last time I read a revised edition of The Negative (from the '60s), Adams mentions that he was embarrassed by the redundancy of the 'previsualization' term, after someone pointed it to him.

It's a fathomable error, considering that seeing a finished picture could be an instance of 'visualization', whereas imagining that picture is a pre-visualization. However I think the term 'visualization' is meant to refer to the "mind's eye" rather than the actual eye, so you have {vision; visualization} in order of abstraction, not {visualization; previsualization}