Sky bed2 was clearly never fit for purpose based on basic engineering principles of strength and forces it is required to endure.
I think the severity of the problem couldn't exactly have been foreseen. They never had such an issue with MkI, and so, understandably, they didn't think it would be a problem here. A large part of the reason why it has become a problem, I think, is that many people step onto the end of the beds when fully extended to access their baggage, or sit on the end of their beds. I see this every time I'm on board an A380. Over time, this greatly contributed to the seats drooping. Now, this never happened with the MkI since the beds are not flat - they're angled, and so no one would sit on the end of them or stand on them.
Two years ago was my last time on a Skybed MkI. And, surprisingly, I actually found
the bed (but not the entire space) much more comfortable, since, even though it was sloped, it was nevertheless flat and did not bend into my spine.
I suspect that, at some time, QF will come around to replacing the seats with the new Vantage XL (albeit with the passenger divider in the aisle seats either removed or made removable for those of us travelling in pairs). I don't think they saw much need for it before, since the majority of their A380s are destined for the US, and there was really no competition in respect of J products (
cf Asian carriers). That is no longer the case: AA's hard product is much better; UA's newly announced hard product is much better; and VA's is much better.
If QF can find a way to remedy the droop problem, I would actually prefer them to do so rather than replace the seats with Vantage XL. Whilst I find the 'compartment' or 'suite' type seats very nice, there is nothing like the sense of space that one feels in the QF A380 J cabin. That, no doubt, is in no small part due to the minimalism. And in that respect, the clutter in the EK A380 J cabin is rather overwhelming and claustrophobic.