slop in the pivot joints
Without seeing it firsthand, I have a concern over slop in the lower pivot and seat tube lockup.
I can see that the seat tube is firmly clamped into the main tube, but it looks like it just fits into the lower assembly without a clamp. (Unlike an earlier poster, I take that seat tube sliding noise as the sign of a good fit. The modern longer seat tubes are often machined - perhaps deliberately, with a coarse, circumferential ribbed surface. It makes that distinctive sound when it goes into a properly fitting seat tube. I've had that exact sound on some of my bikes.)
But even if the forward bearing is a perfect fit, what about the slop of the seat tube going into the lower assembly? That's got to produce some rocking. If anyone here has one, how about some close up pictures of that seat tube fit into the lower assembly.