You'd think by now they would have either done it right or dropped the idea. The fact that the current problem, though slightly different, is still with the adapter/connector should tell them something. They need to spend far more time and money to get it right or simply stop wasting time and move on.
Can't say I want to be one of their guinea pigs.
the prevalence of this new issue is nowhere near the scope of the 2006 issues. back then, the weak connector near the magsafe end couldnt support the strain most users subjected it to. most of the articles online are about this issue. apple redesigned the adapter with a stronger and longer connector and the issue went away. in other words, apple fixed the problem.
this new problem that has cropped up is quite different from the previous issue. it may have similar symptoms, but it is not due to the weakness of the connector near the magsafe end. there haven't been widespread problems for over 2 years now. as far as I know, the OP's issue is not widespread either.
yes, the design could be improved more... as others have said, the end near the brick could use some strengthening, but I think it's faulty logic to state the adapters havent been improved since their introduction
it's possible the newer models have design flaws the older ones did not