Lomcevak/spocla
I don't want to interfere in your mutual appreciation society. While I find your descriptions and lessons on the precise use of language interesting, when it comes to stability derivatives I think it's easiest to just calculate the eigenvalues!
However, going back to the original question of why a low wing Tupolev has anhedral, I proposed my Dutch Roll hypothesis as an alternative to Rainboe's control force argument, Milt's wing flex idea (ie, that when the wing flexed up in flight it wouldn't really have anhedral) and Spocla's cross-wind landing issue.
My vote remains with Dutch Roll.
Lomcevak - by the way, I didn't say anhedral was used to improve Dutch Roll damping. It reduces the yaw-roll coupling.
Also, see this about SpaceShipOne...
Shane said all the pilots had to deal with the Dutch roll, noting it was the price of not having a yaw damper for simplicity. Tighe said the high-wing configuration naturally increases roll-yaw coupling dihedral effect, which together with weak damping from the short span leads to the problem. He noted many airplanes with swept high wings have anhedral to reduce the coupling, but this was not possible in SpaceShipOne because of the need for a straight hingeline across the span for the feather mechanism. He awaits flight test to see how the craft really flies. It turned out there was a data error in the simulation that caused a bobble while decelerating through Mach 1.
If Dutch roll is a serious problem, one solution could be to add anhedral wingtip extensions. A yaw damper is also a possibility. Tighe noted that the oscillation is just slow enough that the pilot with practice can reduce it, but he would be reluctant to try this in flight for fear of getting out of phase. The Dutch roll parameters in the simulator were estimated by computational fluid dynamics and one hopes that actual behavior does not go beyond nauseating to hazardous.