Yes,I think that Hans Asberger's discussion of autistic psychopathy is still relevant.The disorder is still somewhat vague to thid day so Asberger's discussion is as good as anyone elses.The disorder is also named for him so he has a lot of respect in the particular community.Just because his methods were not always foolproof doesn't mean his research wasn't valid.
I have read that when Hans Asperger coined the diagnostic term of "autistic psychopath", he was referring more to a sociopath. I do not believe this. I believe there are levels or degrees in any illness. If you look at many of the mass killings over the last few years, you see it mentioned that the person who committed the crime had "a form of autism". Perhaps then the diagnosis of "autistic psychopathy" is acutely valid.
Hans Asperger developed a way to diagnose autism. As with most disorders, diseases, and syndromes, autism is largely defined by its symptoms. There are modern tests and practices that may reveal a truer diagnosis, but even those are not perfect. Using that which Asperger developed to start someone into the support structure for autistic children or even adults can provide necessary relief for the symptoms even if the cause is not autism. Having treatment that involves the peculiarities that both are, or mimic autism can make all the difference. As more concise ways are implemented to identify autism or prove the symptoms are due to something else, they can be helpful to support the current system.
As a guide his diagnosis should be used in order to inform his decision and give parents a general idea of what they should expect from their children. While today his diagnosis would be considered as part of the autism spectrum, rather than a discreet disorder, it is still a general idea.
Hans Asperger's diagnosis of autistic psychopathy is not still relevant because the belief in it prohibits the advances of theories that have come after it. It also prohibits changes in how autistic psychopathy is treated. Doctors cannot advance beyond it if they are still stick on this one theory of the disease.