Hi JetX, there have been plenty of experienced guys go through flight screening and on to have good RAAF careers. You are definitely not the first and won't be the last. Some are flying fighters with the majority flying the heavier iron. Ironically some are flying the aircraft they left the airlines to get away from, all be it less airtime and more ground work per flight hour. However the generally find these airborne hours more rewarding and varied.
I have come across some guys that have seen the reality and realised that it isn't what they hoped and are now trying to go back, however they are now stuck with a minimum period of service to complete. I hope these guys stick it out and see that all is not bad and it can be a very rewarding career with many varied challenges. What airline pilot doesn't want to fly a 737 thirty feet from another airliner- or very shortly at 200' ASL. Please keep your motivation in check as it will be tested when the log book hours slow down. Be happy that one hour in a Hornet is worth 100 in the 787 when it comes to enjoyment. After all 250 fast jet hours a year is flying everyday. 550 maritime in the P3 or P8 when you get there, is more sporadic, but being below safety height at night chasing a nuclear sub is very challenging!
I wish you all the best and hope that you are one of those guys that should have joined the airforce in the first place!