I too find it hard to see what good will come of "an even more diverse group is being treated as one".
My sister, who has a dx of Aspergers, is pretty mild in terms of her ASD 'symptoms' and can live (largely) independently and (with a degree of difficulty) hold down a job. Her more severe needs are her mental health needs: severe depression, self-harm etc.
J has those MH needs too but this is accompanied by what the ADOS and CARS scores show as severe autism...but he isn't, not in the sense of functioning. He's in mainstream, very very verbal, pretty able academically in areas he likes e.g. ICT/ history but needs 1:1 aand supervision 24 hours a day. He has no sense of danger whatsoveris very violent and volatile in many situations but meek and mild in others (usually when very relaxed at home).
There are some similarities between J and my sister but I would definitely not just lump them both together as the same thing because my sister has far more independence than J will ever have. Yet she is obsessive in her need to compete with him and gets very upset that he gets high rate DLA and a full-time Statement and the offer of direct payments because she never had them. 'But we're both autistic', she wails...she can't see that they are poles apart, both from each other, and also from someone with autism who is non-verbal and has learning disabilities (which neither of them have).
Autism isn't one thing and I don't see the benefit of pretending that it is except for those people like my sister (and their parents). She sees the 'all-in-one' classification as a way to validate her difficulties and stop people saying 'well, it's only mild Aspergers' (which it is) as she feels she'll then be able to say 'I'm autistic' and access more services (cos here autism dx = services and Aspergers dx = f all).
It has no benefit, in my eyes, for anyone anywhere further along the spectrum and I don't understand how this will make it easier for anyone except the people giving the dx as now there will be no debate about what to put on the dx report. However, this also leads to a lack of clarity which makes appropriate support harder to provide.