1. The most sit-up-and-take-notice change is the total removal of Rett syndrome from the DSM. It is gone. The DSM-V people are saying, "genetic syndromes don't belong in our book," or words to that effect, and I agree.
2. Indeed the vast majority of named neurodevelopmental disabilities do not appear in the DSM, past, present, or future. This raises the question of why autism is there. Rett's being excluded is not going to immediately result in Rett's individuals being catastrophically deprived of recognition or assistance. Instead it may result in these individuals being regarded more accurately, to their great benefit. Removing autism from the DSM would have the same beneficial effect.
3. Another change to grapple with: CDD (Childhood Disintegrative Disorder) is now lumped in with autism, which in turn has a single vaguely phrased onset criterion. To cover CDD (Volkmar et al., 2005), that criterion will have to cover onset at age 5 (fairly common in CDD) and up to age nine (rare, but happens).
4. In addition, autism and CDD have very different cognitive profiles. This is one of many ways in which the DSM-V, even more than its predecessor, is running away from the productive and beneficial--to autistics--notion of autism as a cognitive phenotype.
5. The headline-making but most predictable--and most predictably responded to--change is the loss of Asperger's and PDD-NOS, which have both always been considered part of the autistic spectrum, as distinct-from-autism diagnoses. Whatever their shortcomings, the loss of these diagnoses is another signal that autism is, officially and more so than ever, merely a series of deficits in overt typical behaviour.
6. At the very least, the DSM-V strongly discourages any view of autism as an atypical cognitive phenotype involving relative (to nonautistics) cognitive strengths and weaknesses.
7. The changed criteria, which collapse the DSM-IV social and communication domains, overlook any role for manual and oral motor abilities in these two areas. And whose definition of the now-mandatory social reciprocity criterion will prevail? Here is John Constantino's one-way-street definition:
Reciprocal social behavior refers to the extent to which a child engages in emotionally appropriate turn-taking social interaction with others.The closer-to-equal time, so to speak, now granted the previously-relegated RIRB (restricted interests and repetitive behaviours) domain could be seen as progress, ditto the disappearance of the "nonfunctional" assumption. But autistics will no longer have DSM-IV unusually focused and intense interests (a strength), we will instead be pathologically fixated.
8. The vagueness and subjectivity of the criteria should later be elaborated on with explanatory text which may add or subtract clarity. And the highly-publicized DSM-V effort to rank and classify all autistics according to a rigid hierarchy of "severity" is as yet missing. How the DSM-V will handle aspects of the by-far most important distinction within the autistic spectrum--the idiopathic vs etiological autism distinction (and see genetic syndromes, above)--remains to be seen.
9. While the DSM-V has enormous political clout, what might change in actual diagnostic practices is unclear. Clinicians and entities currently employing anything-goes or free-for-all and/or expedient-type standards are unlikely to change in this respect. And in many ways DSM-V autism is autism altered to conform to the current "gold-standard" autism diagnostic instruments (see the role of Catherine Lord in both), whose predominance, weaknesses and limitations have come to determine what autism is and isn't.
10. Organizations which (a) have little use for basic autism research (the kind I'm involved in) or actually oppose it; and (b) promote political views of autism, including that more services are always better--will likely be happy with the DSM-V changes. You can see ASAN fulfill this prediction here.
Volkmar, F.R, Koenig, K., & State, M. (2005). Childhood Disintegrative Disorder. In: Volkmar, F.R., Paul, R., Klin, A.,Cohen, D. (Eds.), Handbook of Autism and Pervasive Developmental Disorders . Hoboken, NJ: Wiley.
Postscript: Another view of the new autism criteria is here. An overview of the proposed DSM-V in many areas is here.