Maybe it's the use of the latest technology which helps a website escape the death grip of Panda.
In my niche I see a broad mix of winners, including some that are totally old-school. However, if this is true it could be because newer sites are using these technologies to create a better user experience, rather than being specifically due to the technologies themselves. Granted, that's a bit of an optimistic view of the use of AJAX and HTML5, but still...
Also, just a small technical quibble:
AJAX generally uses js onClick events where older technology use anchor tags.
Yeah, people often do it that way but that's not the best way to do it IMO. It is better to code a straight anchor and then use JS to modify the onclick behavior of the anchor so it runs the script instead of clicking through. That way your links work even with JS disabled. Colorbox does this, for example. If you do it right, you can use all kinds of JS and AJAX and still have the site function with JS off - and you can get some nice improvements in apparent performance, for example by loading content from other pages after the page loads so that it displays instantaneously on click.
If sites are getting a boost for being broken with JS turned off, that's a step in the wrong direction with respect to quality if you ask me.
Besides, I suspect Google has been following most common usages of JS links for some time anyway.