I don't think anyone is suggesting we'd send crews to sleep under Caribou wings - that was never going to work in reality, even when we practiced it.
Nor would I want to go back to trying to coax old airframes and engines to hang together just that little bit longer to get the job done - too unreliable and costly.
I'd like to see rigorous assurances given that a re-engined Caribou wouldn't run into problems with airframe fatigue as put the final nail in the RAAF Caribou coffin, but if that could be done it'd be a great asset.
We can get all theoretical about what Australia's future role in conflicts might be, but the type has proven itself over and over in the afore-mentioned disaster relief work, which is undeniably a very important part of our defence presence in the region.
The development of skilled aircrew in a relatively low-cost, capable platform is not to be dismissed either, if we're to maintain a robust pool of operators with surge capability. Instead of spending gazillions on a small number of really expensive aircraft that are hard and costly to maintain, it makes sense to me to mitigate the situation somewhat by having a cheaper machine that flies heaps of hours, does lots of work, keeps the Army happy because it can turn up reliably, and provides some of the most useful and challenging flying available to Australian crews by allowing ops into most of the strips in PNG.
As for battlefield survivability, I'd suggest a Chinook would be just as vulnerable as a turbo Caribou fitted with equivalent countermeasures.
This isn't sentimentality speaking - trying to resurrect old buggered Caribous, as we did for a long time, was a losing battle. However, the sheer usefulness of the type makes it well worth considering for replacement with a revamped, reliable equivalent.
How much is a Pen Turbo Bou, Bushy 71, do you know? I bet you could get a bunch of them for the cost of a C-27, and maintain them for a lot less.