While classic NAT technologies serving the purpose of saving valuable address space have been known for a long time (when measured in Internet-time) other uses for this technology have been found, that are independent of the problems NAT was proposed to help to solve. That means, NAT will not be obsoleted by the long term solutions (like IPv6) developed to solve all of the problems discussed at the beginning of this paper, since completely new fields of application have been found.
Some of these new technologies are introduced below. I write 'some', because I am sure more are to follow that nobody even dreams of today. Not that NAT is vitally important, we could probably live without it somehow, but that is true for many more things developed or invented in the past X*1.000 years. It just can make life easier sometimes. It can also make it harder -- again, this is true not only for NAT, since everything can be used for good and bad.