One of the many reasons I'm very peeved about the exclusion of AS from the DSM-5 is that it took me years to figure out what condition I have, and now, they're going to take it away and say that I don't qualify?
I'm a strong proponent that AS and HFA are NOT the same, which is the main reason I'm against this change, but regardless of that part of it, I think it is silly to call everything "autistic disorder" and use severity. All of us on the spectrum know very well that there is a vast difference in functioning among so-called "high-functioning" individuals alone. According to their proposal, all high-functioning people would be level 1. Just because I was able to get through school/life without accommodations due to my high IQ and lack of knowing what AS was during childhood means that I'm not on the spectrum and that I don't struggle living each day?! It is garbage and going to make the diagnostic process even more muddled.
I do think that ASD diagnoses are being overdiagnosed in the last few years. It's the new ADHD. But that doesn't mean that we shouldn't keep the label of Asperger's or PDD-NOS. People are just starting to know what AS is and that PDD-NOS is "atypical autism," and they're going to go around and undo all the progress that's been made in educating the public. I also highly dislike the proposal to take OCD out of the anxiety disorders and make a section JUST for OCD-spectrum disorders. The whole POINT of OCD is the anxiety! That FUELS it! To say it's not an anxiety disorder makes NO sense.
Personally, I think the "spectrum" idea is going too far. It's a good technique to explain differing severities of disorders, but to classify conditions with a spectrum alone is poor. Yes, disorders aren't black-and-white categories, but spectrum ideology is making overdiagnosis. This isn't just for ASDs, either. Bipolar disorder is becoming like this, too. The idea of bipolar spectrum disorders is lame. Yes, bipolar disorder can take many different forms, but we don't need bipolar 1/2 and bipolar 1 1/2, for crying out loud! (And yes, those are being proposed by some bipolar researchers.) Bipolar I, II, III, and IV are completely sufficient.
The DSM sucks as it is for most disorders. OCD, mania, and ASDs are all poorly described in terms of their symptoms in the DSM-IV. But rather than improve explaining what the disorders are so people can actually recognize that they have a condition, they are just making the criteria even MORE vague and blurred. It really angers me, because the new edition is supposed to make the disorders' descriptions BETTER. So many things are currently missing from diagnostic criteria, and none of those things are going to be added/changed. Is it any wonder so many people are being incorrectly diagnosed and/or not diagnosed at all? The reason I slipped through the cracks for so many years is because my forms of OCD and Asperger's are not the stereotypical cases presented in the DSM. And so few people know that mania is the most common form of psychosis after schizophrenia, and why is that? Because it's never even MENTIONED in the DSM that mania is often a psychotic state. 
_________________
Helinger: Now, what do you see, John?
Nash: Recognition...
Helinger: Well, try seeing accomplishment!
Nash: Is there a difference?