Nokian WR is the only tire I found appropriate. They say snow performance is "not good" after they are worn down past 4, but the sipes are designed to be useful all the way down to the wear bars. I tried it on snow thanks to a freakishly early snow storm and they were actually still better than all-seasons even with only 2mm of tread left.
the Conti DWS is only a "DW" after basically one season. Even some of the other tires wear down the snow traction compound very fast... and they wear down whenever they are dry roads, even in the cold. That's just not acceptable.