Weighting on backlinks has changed massively. Websites with very few links now rule many competitive SERPs. Sitewide backlinks seem to have lost most of their weight, and more links than ever are being discounted.
Right now we also see many spammy blogs (no content at all) ranking very high again for very competitive terms. Hope this is just a small glitch and in January we can se the real deal. As for backlinks, agree with you: sites with no backlinks at all started ranking high - while established sites gone down.