Challenge and response involves both pilots in an active way. Yes, it's still possible to miss items, but the system was better than what we have now.
We have aready had one incident in my airline as a direct result of the new procedures.
Can other Boeing drivers confirm that this is the way it's done on 74, 75, 76 and 777 fleets? FO does, reads and answers most preflight actions with the captain only responding to a few items?