The Australian Bishops tried that in 1996 when they required Church officials to comply with civil reporting laws, contrary to canon law at the time. In 2002, the Vatican agreed that U.S. civil reporting laws should be followed, and in 2010, it extended that to the rest of the world. In the same year the Australian bishops amended Towards Healing to require mandatory reporting in all cases, irrespective of civil laws. In 2013, the CDF told them that they could have it for everyone else except clergy. What you propose has been tried and it does not work, because Church officials take oaths to obey canon law, and any such protocol is not binding on any bishop without the approval of the Vatican. What the bishops really should do is publicly disagree with Pope Francis over his rejection of mandatory reporting in all cases. If Cardinals can issue a “correction” to a pope over matters of doctrine, then surely, they can do it for canon law.