I'm with Homeguard on this one , I do not think that the quality of instructors is poor, what I do know is that all FI holders have demonstrated skill and knowledge to a certain standard and have demonstrated committment and staying power. Most of my colleagues are well trained, confident, outgoing and well capable of teaching students how to fly and make good decisions
I am a "mature" self improver with a lot of experience as a PPL holder under my belt, most of my colleagues are fast track academy graduates and they are good instructors !
Maybe it depends on the standard of the school that you work at ? and the standard set at interview / check flight.