The process you are describing can be very effective. My last posting before I left was as an instructor with BOWTAG (South) where everyone was at least 18 yrs+ in terms of service and not everyone was fully fit (for a variety of reasons). The point is that we were all SMEs, could be relied upon to prepare and deliver training with no supervision and could also deploy into theatre to deliver training if required.No training, but I deployed the team a number of times* and never had an issue with delivering effect and was never told there was a shortcoming, so I just cracked on. To be fair, it was only one element of the role, but there was little unit support from the training wing who, even if they had been more flexible and proactive, had little or no resources.
*including a senior SSgt who hadn't deployed for years as others were to lazy or risk averse to manage his medical requirement.