I will give Qantas some credit here. I'm sure accountants everywhere will agree, improving the points plus pay conversion rate from 0.6c to 1.0c at this scale is not an insignificant change. If it's true that Qantas sells points to banks at around 1.0c then these points are now unprofitable.
I think lots of people will redeem their points at 1c. Lots of people are already paying cash for Qantas fares (even if they are as some would say overpriced) so I don't see why they would not cash in their points for 1c.
I do agree that classic rewards chasers will remain disappointed however I don't recall reading any other realistic suggestions to fix this problem. Even if Qantas released more classic reward seats at 2x the classic reward price we all know that all the J seats will sell out within 24 hours and we are back at square one. I actually think that if all J seats on the QF network were converted to classic rewards, even at 2x the classic reward price, all of the international seats will sell out within days.