I got to thinking about this again. As far as Panda-theory goes, there are no conclusions.
All of these have been suggested as the reason for a Panda hit:
content reading level
I'm sure there are a ton more.
The thing is, thousands of webmasters have been working for one or two months now making changes. And compared to these thousands of people, only the very smallest percentage, if any, have reported success in their efforts.
That can only suggest, as I mentioned some time ago, that Panda has some sort of time element associated with it (either as a true penalty, or so to continue to get people to clean up the web on their own, or by design, or because google has some sort of problem at their end).
But there is no way that out of thousands of people, taking 100's of different fix-it approaches, that no one has made changes that can satisfy this algo. The "figure out this algo" approach can't work if no testing can be performed.
That means the thing to do now is simply make your site the best it can be. Surely, all of us know where the deficiencies of our websites lie.