Obviously up with proposed changes
The organisation hasn't shrunk recently either. CASA have gone about this completely the wrong way and blatantly obvious they haven't done a risk analysis to determine the possible outcomes of CASA's actions. From a safety and a financial perspective I would say it's time to think about splitting the AOC in two - have a separate chief pilot for the smaller aircraft with more junior pilots, and one for the more experienced guys on the turbine. A little bit of pain involved with separate Ops manuals, 20.11's, CAR217 systems, etc. But a second (or third and fourth if you include HOTAC) set eyes of to keep an eye on the operation and ensure everything is by the book wouldn't go astray with such a large, busy organisation with a diverse fleet. Also may limit the damage if CASA takes an interest in a particular AOC.
I can imagine operators embracing your mandated structural change. They would love to have to pay for it as well and then have to change it all back when Part 119 kicks in. You should get a hold of JH and put your proposal forward but let me know when you do, I would love to watch.