Steve, there could be merit in using a shared monitored approach. The more experienced pilot, relieved of the flying workload might have detected the deteriorating situation earlier. However, this view should not assume that the more experience pilot will always provide a better understanding or have sufficient mental resource for establishing the situation and deciding to act. Also, there are some very experienced and capable First Officers in the industry – yet over time we all have to learn and thus could be vulnerable at some point.
An encouraging aspect is that many HF texts relate decisions to the quality of understanding; thus any procedure which enhances situation awareness and use of experience to aid understanding should contribute to safety.
Too often the industry, and as in this thread, assumes that the monitoring pilot will be able to understand the situation and decide to act. It is equally likely that in this accident the FO/PM crossed-checked the PF displays to improve his understanding, and noticing the disparity, accepted the PF display and actions as being better than his, thus there was no intervention.
Based on what we now know this view might be considered as a failure in understanding and intervention (hindsight bias), but the behaviour was exactly the same as would expected if the Capt/PF displays were correct and the FO/PM were in error; the disparity might have been noticed but not commented on, except with good mentoring the Captain could have debriefed it after landing.
A problem in some parts of the industry is the belief that SOPs and CRM (human activity) will provide adequate safety in all circumstances. This is not an anti SOP / CRM view, but acknowledging that these tools have limits in particular circumstances, which operations appear to be encountering more frequently.
Thus anything which questions this attitude and considers alternative procedures will be of benefit.