Originally Posted by Geezer
The instability you're feeling probably has more to do with the softer tread compounds and tire siping than tread width. Taller sidewalls (especially one ply ones) will often add to the feeling. It's the price you pay for optimum snow and ice grip.
I run performance winter tires so I get less of that squishy feeling due to the compound and tread design. They cost a little more, but they are totally worth it when your winter consists of 90% dry pavement.