We have one site filtered with a ton of dupe, surprised it has stayed this long( about 4 years) but it has a ton of mega strong links from when we bought it. I got so used to seeing it in the serps I thought google would never take it out. It was a pr 7 when we bought it, still is a 6.
Should not have been so lazy and made some more content.
I think this thread with "I am seeing no changes"etc is only relevant to those of you who have similar sites.
So I can with 99% certainty say that google is now notching up filtering sites that have too much related content.