How do they do it in civi street, how do BA etc run their first line techie worlds. You don't have to be a Cpl to oversign you just have to be suitably competent. You can get paid for getting more quals and taking on extra responsibility without being promoted. Is there a requirement at this level to have rank and responsibility so closely tied.
If you want reform of the RAF it needs to be done by people ready to challenge those above them, and try not to feather their individual nest, unfortunately only yes men seem to get on so all we end up doing is going from balls up to balls up.
But you also need to keep some sort of rank structure, we are a military force after all.