How many times is this that the RAAF have looked for a true replacement for the Caribou?? It's been going on for decades - back to when the F-27 was being considered. I don't blame them for wanting to get rid of the R2000 round engines! (Although I'll miss that great sound!)
The only aircraft to replace the Caribou's unique performance - is another Caribou, preferably with PT6A-67's or PW100 engines!!!
I believe the RAAF DHC4's have only 15,000 to 20,000 hours on the airframes. One would think it important enough to retain their unique STOL capability, to completely refurbish and update engines to turbines, whilst also buying a mid size transport?