He said whoever replaced him would bring a new perspective.
"Some fresh eyes, some fresh thinking ... whoever it is will be fresh. It will be for the enhancement of the legacy of the jersey," he said.
Hansen comes off contract with New Zealand Rugby (NZR) after the tournament, which runs next September and October.
He has been Head Coach of the All Blacks since 2012 and prior to that was an Assistant Coach for eight years.
Hansen told media this morning two big reasons for making the choice were what was right for the team, and what was right for his family.