Had many long haul flights flying with Qantas, a great airline with a great reputation in having never lost a life or airframe unlike the world's favourite airline.
Still more frightening doing a controlled depressurised decent 20,000 feet, when parts of the plane have just left the hull, than a storm when you are on the ground IMO. Sure you have had many good Qantas flights, there is a lot of concern with their currently policy of outsourcing a lot of functions and running old craft e.g.the one with the problem was 17 years old. There is a concern that Qantas repair things now that others would not to keep that reputation.
Cause of problem is unknown and speculation seems to be around 3 causes, either way crew did a great job and all were safe.
You are right i first flew on this type (747-400) back in 92, they need the delayed Airbus A380 they have on order to start arriving soon to replace some of the older aircraft. I think they get the first soon.
The one i know they repaired landed long at Bangkok and ended up on the golf course, they repaired the hull to maintain their no lost hull's record.
Boeing need to get on and develop the 747-800........but not sure it will ever see the light of day.
But at the end of the day the 400 was and still is a fantastic aircraft.