Iro considers New Zealand "still slight favourites for the whole tournament", crediting a forward pack that dominated opponents, including Australia in the opening round.
For Saturday's semi-final against Tonga, he would keep Kalyn Ponga on the bench rather than immediately restore him to the starting side.
Ponga is in the reserves after breaking his arm against Australia in the tournament opener and undergoing surgery; Keano Kini is expected to retain the No. 1 jersey.
"I think I'd leave Kalyn on the bench. I think they probably would have trained all week with Keano obviously in the number one jersey."
Iro believes Ponga could provide a late attacking lift, while another week's recovery may help if New Zealand reaches next week's final.
He expects Tonga to target Charnze Nicoll-Klokstad, who has moved to the wing for suspended Ronaldo Mulitalo.
Iro rates Robert Toia the game's best centre, with Casey McLean close behind, and praised Dane Gagai as an unsung hero for his defence and State of Origin experience.