The issue of long term back filling is having several long term impacts on employees and departments.
I myself backfilled in the same role for 8 years and each year I would need to do an EOI for my positon. The sense of job security is not good and can impact on your personal life and health. The insecurity for your teams is also and issue and as a department the number of people backfilling is very large so again there is no stability. The state government looked at this a while ago and made a decision if you can back fill for 2 years then you will become permanent in that role.
I hope that the issue of long term backfilling is one that can be looked at and I am happy to discuss more if needed